diff --git a/CHANGES.rst b/CHANGES.rst
index 3bab7f1..83ed2cb 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -6,7 +6,11 @@ Changes
 
 - Add support for Python 3.7.
 
-- Drop support for Python 3.3.
+- Drop support for Python 3.3 and remove internal compatibility
+  functions needed to support it. See `issue 20
+  <https://github.com/zopefoundation/zope.configuration/issues/20>`_
+  and `issue 26
+  <https://github.com/zopefoundation/zope.configuration/issues/26>`_.
 
 - Drop support for ``python setup.py test``.
 
diff --git a/docs/api/fields.rst b/docs/api/fields.rst
index f7c65cd..dd542dc 100644
--- a/docs/api/fields.rst
+++ b/docs/api/fields.rst
@@ -189,8 +189,7 @@
    .. doctest::
 
       >>> import os
-      >>> from zope.configuration._compat import u as unicode
-      >>> p = unicode(os.path.join(os.sep, 'a', 'b'))
+      >>> p = os.path.join(os.sep, u'a', u'b')
       >>> n = field.fromUnicode(p)
       >>> n.split(os.sep)
       ['', 'a', 'b']
@@ -208,7 +207,7 @@
 
    .. doctest::
 
-      >>> p = unicode(os.path.join('a', 'b'))
+      >>> p = os.path.join(u'a', u'b')
       >>> n = field.fromUnicode(p)
       >>> n.split(os.sep)
       ['', 'faux', 'context', 'a', 'b']
diff --git a/src/zope/configuration/_compat.py b/src/zope/configuration/_compat.py
index 650fdde..a7d8286 100644
--- a/src/zope/configuration/_compat.py
+++ b/src/zope/configuration/_compat.py
@@ -15,20 +15,12 @@
 
 PY3 = sys.version_info[0] >= 3
 
-if PY3: #pragma NO COVER
+if PY3: # pragma: no cover
 
     import builtins
-    from io import StringIO
 
-    string_types = str,
+    string_types = (str,)
     text_type = str
-    def b(s):
-        return s.encode("latin-1")
-    def u(s):
-        return s
-
-    # borrowed from 'six'
-    print_ = getattr(builtins, "print")
 
     # borrowed from 'six'
     def reraise(tp, value, tb=None):
@@ -38,63 +30,12 @@ def reraise(tp, value, tb=None):
             raise value.with_traceback(tb)
         raise value
 
-else: #pragma NO COVER
+else: # pragma: no cover
 
     import __builtin__  as builtins
-    from StringIO import StringIO
 
     text_type = unicode
-    string_types = basestring,
-    def b(s):
-        return s
-    def u(s):
-        return unicode(s, "unicode_escape")
-
-    # borrowed from 'six'
-    def print_(*args, **kwargs):
-        """The new-style print function."""
-        fp = kwargs.pop("file", sys.stdout)
-        if fp is None:
-            return
-        def write(data):
-            if not isinstance(data, basestring):
-                data = str(data)
-            fp.write(data)
-        want_unicode = False
-        sep = kwargs.pop("sep", None)
-        if sep is not None:
-            if isinstance(sep, unicode):
-                want_unicode = True
-            elif not isinstance(sep, str):
-                raise TypeError("sep must be None or a string")
-        end = kwargs.pop("end", None)
-        if end is not None:
-            if isinstance(end, unicode):
-                want_unicode = True
-            elif not isinstance(end, str):
-                raise TypeError("end must be None or a string")
-        if kwargs:
-            raise TypeError("invalid keyword arguments to print()")
-        if not want_unicode:
-            for arg in args:
-                if isinstance(arg, unicode):
-                    want_unicode = True
-                    break
-        if want_unicode:
-            newline = unicode("\n")
-            space = unicode(" ")
-        else:
-            newline = "\n"
-            space = " "
-        if sep is None:
-            sep = space
-        if end is None:
-            end = newline
-        for i, arg in enumerate(args):
-            if i:
-                write(sep)
-            write(arg)
-        write(end)
+    string_types = (basestring,)
 
     # borrowed from 'six'
     exec("""\
diff --git a/src/zope/configuration/config.py b/src/zope/configuration/config.py
index 8b41420..09871cf 100644
--- a/src/zope/configuration/config.py
+++ b/src/zope/configuration/config.py
@@ -35,7 +35,7 @@
 from zope.configuration._compat import reraise
 from zope.configuration._compat import string_types
 from zope.configuration._compat import text_type
-from zope.configuration._compat import u
+
 
 
 zopens = 'http://namespaces.zope.org/zope'
@@ -621,10 +621,11 @@ class IDirectivesInfo(Interface):
     """
 
     namespace = URI(
-        title=u("Namespace"),
-        description=u("The namespace in which directives' names "
-                      "will be defined"),
-        )
+        title=u"Namespace",
+        description=(
+            u"The namespace in which directives' names "
+            u"will be defined"),
+    )
 
 
 class IDirectivesContext(IDirectivesInfo, IConfigurationContext):
@@ -642,35 +643,39 @@ class DirectivesHandler(GroupingContextDecorator):
 
 
 class IDirectiveInfo(Interface):
-    """Information common to all directive definitions have
+    """Information common to all directive definitions.
     """
 
     name = TextLine(
-        title = u("Directive name"),
-        description = u("The name of the directive being defined"),
-        )
+        title=u"Directive name",
+        description=u"The name of the directive being defined",
+    )
 
     schema = DirectiveSchema(
-        title = u("Directive handler"),
-        description = u("The dotted name of the directive handler"),
-        )
+        title=u"Directive handler",
+        description=u"The dotted name of the directive handler",
+    )
+
 
 class IFullInfo(IDirectiveInfo):
-    """Information that all top-level directives (not subdirectives) have
+    """Information that all top-level directives (not subdirectives)
+    have.
     """
 
     handler = GlobalObject(
-        title = u("Directive handler"),
-        description = u("The dotted name of the directive handler"),
-        )
+        title=u"Directive handler",
+        description=u"The dotted name of the directive handler",
+    )
 
     usedIn = GlobalInterface(
-        title = u("The directive types the directive can be used in"),
-        description = u("The interface of the directives that can contain "
-                        "the directive"
-                       ),
-        default = IConfigurationContext,
-        )
+        title=u"The directive types the directive can be used in",
+        description=(
+            u"The interface of the directives that can contain "
+            u"the directive"
+        ),
+        default=IConfigurationContext,
+    )
+
 
 class IStandaloneDirectiveInfo(IDirectivesInfo, IFullInfo):
     """Info for full directives defined outside a directives directives
@@ -752,12 +757,12 @@ class IProvidesDirectiveInfo(Interface):
     """Information for a <meta:provides> directive"""
 
     feature = TextLine(
-        title = u("Feature name"),
-        description = u("""The name of the feature being provided
+        title=u"Feature name",
+        description=u"""The name of the feature being provided
 
         You can test available features with zcml:condition="have featurename".
-        """),
-        )
+        """,
+    )
 
 def provides(context, feature):
     """Declare that a feature is provided in context.
@@ -935,8 +940,8 @@ def __str__(self): #pragma NO COVER
         for discriminator, infos in sorted(self._conflicts.items()):
             r.append("  For: %s" % (discriminator, ))
             for info in infos:
-                for line in text_type(info).rstrip().split(u('\n')):
-                    r.append(u("    ") + line)
+                for line in text_type(info).rstrip().split(u'\n'):
+                    r.append(u"    " + line)
 
         return "\n".join(r)
 
diff --git a/src/zope/configuration/fields.py b/src/zope/configuration/fields.py
index dd8405e..bb27c07 100644
--- a/src/zope/configuration/fields.py
+++ b/src/zope/configuration/fields.py
@@ -30,9 +30,9 @@
 
 from zope.configuration.exceptions import ConfigurationError
 from zope.configuration.interfaces import InvalidToken
-from zope.configuration._compat import u
 
-PYIDENTIFIER_REGEX = u('\\A[a-zA-Z_]+[a-zA-Z0-9_]*\\Z')
+
+PYIDENTIFIER_REGEX = u'\\A[a-zA-Z_]+[a-zA-Z0-9_]*\\Z'
 pyidentifierPattern = re.compile(PYIDENTIFIER_REGEX)
 
 
diff --git a/src/zope/configuration/interfaces.py b/src/zope/configuration/interfaces.py
index 8990ad6..67ee132 100644
--- a/src/zope/configuration/interfaces.py
+++ b/src/zope/configuration/interfaces.py
@@ -16,7 +16,7 @@
 from zope.interface import Interface
 from zope.schema import BytesLine
 from zope.schema.interfaces import ValidationError
-from zope.configuration._compat import u
+
 
 class InvalidToken(ValidationError):
     """Invaid token in list."""
@@ -31,14 +31,14 @@ class IConfigurationContext(Interface):
     """
 
     package = BytesLine(
-        title=u("The current package name"),
-        description=u("""\
+        title=(u"The current package name"),
+        description=(u"""\
           This is the name of the package containing the configuration
           file being executed. If the configuration file was not
           included by package, then this is None.
           """),
         required=False,
-        )
+    )
 
     def resolve(dottedname):
         """Resolve a dotted name to an object
diff --git a/src/zope/configuration/tests/conditions.py b/src/zope/configuration/tests/conditions.py
index a8283cc..b79fdce 100644
--- a/src/zope/configuration/tests/conditions.py
+++ b/src/zope/configuration/tests/conditions.py
@@ -16,17 +16,15 @@
 from zope.interface import Interface
 from zope.schema import Id
 
-from zope.configuration._compat import u
-
 
 class IRegister(Interface):
     """Trivial sample registry."""
 
     id = Id(
-        title=u("Identifier"),
-        description=u("Some identifier that can be checked."),
+        title=u"Identifier",
+        description=u"Some identifier that can be checked.",
         required=True,
-        )
+    )
 
 registry = []
 
diff --git a/src/zope/configuration/tests/nested.py b/src/zope/configuration/tests/nested.py
index 3d63f9b..f9f930c 100644
--- a/src/zope/configuration/tests/nested.py
+++ b/src/zope/configuration/tests/nested.py
@@ -25,7 +25,7 @@
 from zope.configuration.config import GroupingContextDecorator
 from zope.configuration.config import IConfigurationContext
 from zope.configuration.fields import Bool
-from zope.configuration._compat import u
+
 
 
 schema_registry = {}
@@ -35,11 +35,11 @@ class ISchemaInfo(Interface):
     """
 
     name = TextLine(
-        title=u("The schema name"),
-        description=u("This is a descriptive name for the schema."),
+        title=u"The schema name",
+        description=u"This is a descriptive name for the schema.",
         )
 
-    id = Id(title=u("The unique id for the schema"))
+    id = Id(title=u"The unique id for the schema")
 
 class ISchema(Interface):
     """Interface that distinguishes the schema directive
@@ -75,43 +75,47 @@ def after(self):
 class IFieldInfo(Interface):
 
     name = NativeStringLine(
-        title=u("The field name"),
-        )
+        title=u"The field name",
+    )
 
     title = TextLine(
-        title=u("Title"),
-        description=u("A short summary or label"),
-        default=u(""),
+        title=u"Title",
+        description=u"A short summary or label",
+        default=u"",
         required=False,
-        )
+    )
 
     required = Bool(
-        title=u("Required"),
-        description=u("Determines whether a value is required."),
+        title=u"Required",
+        description=u"Determines whether a value is required.",
         default=True)
 
     readonly = Bool(
-        title=u("Read Only"),
-        description=u("Can the value be modified?"),
+        title=u"Read Only",
+        description=u"Can the value be modified?",
         required=False,
         default=False)
 
 class ITextInfo(IFieldInfo):
 
     min_length = Int(
-        title=u("Minimum length"),
-        description=u("Value after whitespace processing cannot have less than "
-                      "min_length characters. If min_length is None, there is "
-                      "no minimum."),
+        title=u"Minimum length",
+        description=(
+            u"Value after whitespace processing cannot have less than "
+            u"min_length characters. If min_length is None, there is "
+            u"no minimum."
+        ),
         required=False,
         min=0, # needs to be a positive number
         default=0)
 
     max_length = Int(
-        title=u("Maximum length"),
-        description=u("Value after whitespace processing cannot have greater "
-                      "or equal than max_length characters. If max_length is "
-                      "None, there is no maximum."),
+        title=u"Maximum length",
+        description=(
+            u"Value after whitespace processing cannot have greater "
+            u"or equal than max_length characters. If max_length is "
+            u"None, there is no maximum."
+        ),
         required=False,
         min=0, # needs to be a positive number
         default=None)
@@ -134,13 +138,13 @@ def textField(context, **kw):
 class IIntInfo(IFieldInfo):
 
     min = Int(
-        title=u("Start of the range"),
+        title=u"Start of the range",
         required=False,
         default=None
         )
 
     max = Int(
-        title=u("End of the range (excluding the value itself)"),
+        title=u"End of the range (excluding the value itself)",
         required=False,
         default=None
         )
diff --git a/src/zope/configuration/tests/simple.py b/src/zope/configuration/tests/simple.py
index 6f410cc..60c95ff 100644
--- a/src/zope/configuration/tests/simple.py
+++ b/src/zope/configuration/tests/simple.py
@@ -18,20 +18,19 @@
 from zope.schema import Text
 
 from zope.configuration.fields import Path
-from zope.configuration._compat import u
 
 class IRegisterFile(Interface):
 
     path = Path(
-        title=u("File path"),
-        description=u("This is the path name of the file to be registered."),
-        )
+        title=u"File path",
+        description=u"This is the path name of the file to be registered.",
+    )
 
     title = Text(
-        title=u("Short summary of the file"),
-        description=u("This will be used in file listings"),
-        required = False
-        )
+        title=u"Short summary of the file",
+        description=u"This will be used in file listings",
+        required=False
+    )
 
 class FileInfo(object):
 
@@ -41,7 +40,7 @@ def __init__(self, path, title, description, info):
 
 file_registry = []
 
-def registerFile(context, path, title=u("")):
+def registerFile(context, path, title=u""):
     info = context.info
     description = info.text.strip()
     context.action(discriminator=('RegisterFile', path),
diff --git a/src/zope/configuration/tests/test_config.py b/src/zope/configuration/tests/test_config.py
index f894812..1a88397 100644
--- a/src/zope/configuration/tests/test_config.py
+++ b/src/zope/configuration/tests/test_config.py
@@ -1703,9 +1703,8 @@ class ISchema(Interface):
     def test_w_field_missing_but_default(self):
         from zope.interface import Interface
         from zope.schema import Text
-        from zope.configuration._compat import u
         class ISchema(Interface):
-            w_default = Text(default=u('default'))
+            w_default = Text(default=u'default')
         context = FauxContext()
         self.assertEqual(self._callFUT(context, ISchema, {}),
                          {'w_default': 'default'})
diff --git a/src/zope/configuration/tests/test_fields.py b/src/zope/configuration/tests/test_fields.py
index 641e136..282fb00 100644
--- a/src/zope/configuration/tests/test_fields.py
+++ b/src/zope/configuration/tests/test_fields.py
@@ -53,15 +53,13 @@ def test_fromUnicode_strips_ws(self):
 
     def test__validate_miss(self):
         from zope.schema import ValidationError
-        from zope.configuration._compat import u
         pi = self._makeOne()
         with self.assertRaises(ValidationError):
-            pi._validate(u('not-an-identifier'))
+            pi._validate(u'not-an-identifier')
 
     def test__validate_hit(self):
-        from zope.configuration._compat import u
         pi = self._makeOne()
-        pi._validate(u('is_an_identifier'))
+        pi._validate(u'is_an_identifier')
 
 
 class GlobalObjectTests(unittest.TestCase, _ConformsToIFromUnicode):
@@ -74,20 +72,16 @@ def _makeOne(self, *args, **kw):
         return self._getTargetClass()(*args, **kw)
 
     def test__validate_wo_value_type(self):
-        from zope.configuration._compat import u
-        from zope.configuration._compat import b
         go = self._makeOne(value_type=None)
-        for value in [0, 0.0, (), [], set(), frozenset(), u(''), b('')]:
+        for value in [0, 0.0, (), [], set(), frozenset(), u'', b'']:
             go._validate(value) #noraise
 
     def test__validate_w_value_type(self):
         from zope.schema import Text
         from zope.schema.interfaces import WrongType
-        from zope.configuration._compat import u
-        from zope.configuration._compat import b
         go = self._makeOne(value_type=Text())
-        go.validate(u(''))
-        for value in [0, 0.0, (), [], set(), frozenset(), b('')]:
+        go.validate(u'')
+        for value in [0, 0.0, (), [], set(), frozenset(), b'']:
             with self.assertRaises(WrongType):
                 go._validate(value)
 
@@ -167,20 +161,18 @@ def test_fromUnicode_empty(self):
 
     def test_fromUnicode_strips_ws(self):
         from zope.schema import Text
-        from zope.configuration._compat import u
         tok = self._makeOne(value_type=Text())
         context = object()
-        self.assertEqual(tok.fromUnicode(u(' one two three ')),
-                         [u('one'), u('two'), u('three')])
+        self.assertEqual(tok.fromUnicode(u' one two three '),
+                         [u'one', u'two', u'three'])
 
     def test_fromUnicode_invalid(self):
         from zope.schema import Int
         from zope.configuration.interfaces import InvalidToken
-        from zope.configuration._compat import u
         tok = self._makeOne(value_type=Int(min=0))
         context = object()
         with self.assertRaises(InvalidToken):
-            tok.fromUnicode(u(' 1 -1 3 '))
+            tok.fromUnicode(u' 1 -1 3 ')
 
 
 class PathTests(unittest.TestCase, _ConformsToIFromUnicode):
@@ -261,12 +253,11 @@ def __init__(self):
 
     def test_wo_domain(self):
         import warnings
-        from zope.configuration._compat import u
         mid = self._makeOne()
         context = self._makeContext(None)
         bound = mid.bind(context)
         with warnings.catch_warnings(record=True) as log:
-            msgid = bound.fromUnicode(u('testing'))
+            msgid = bound.fromUnicode(u'testing')
         self.assertEqual(len(log), 1)
         self.assertTrue(str(log[0].message).startswith(
                             'You did not specify an i18n translation domain'))
@@ -278,12 +269,11 @@ def test_wo_domain(self):
 
     def test_w_empty_id(self):
         import warnings
-        from zope.configuration._compat import u
         mid = self._makeOne()
         context = self._makeContext()
         bound = mid.bind(context)
         with warnings.catch_warnings(record=True) as log:
-            msgid = bound.fromUnicode(u('[] testing'))
+            msgid = bound.fromUnicode(u'[] testing')
         self.assertEqual(len(log), 0)
         self.assertEqual(msgid, 'testing')
         self.assertEqual(msgid.default, None)
@@ -293,12 +283,11 @@ def test_w_empty_id(self):
 
     def test_w_id_and_default(self):
         import warnings
-        from zope.configuration._compat import u
         mid = self._makeOne()
         context = self._makeContext()
         bound = mid.bind(context)
         with warnings.catch_warnings(record=True) as log:
-            msgid = bound.fromUnicode(u('[testing] default'))
+            msgid = bound.fromUnicode(u'[testing] default')
         self.assertEqual(len(log), 0)
         self.assertEqual(msgid, 'testing')
         self.assertEqual(msgid.default, 'default')
diff --git a/src/zope/configuration/tests/test_xmlconfig.py b/src/zope/configuration/tests/test_xmlconfig.py
index d59bae9..283aa86 100644
--- a/src/zope/configuration/tests/test_xmlconfig.py
+++ b/src/zope/configuration/tests/test_xmlconfig.py
@@ -15,19 +15,18 @@
 """
 import unittest
 
-from zope.configuration._compat import u
-
-NS = u('ns')
-FOO = u('foo')
-XXX = u('xxx')
-SPLAT = u('splat')
-SPLATV = u('splatv')
-A = u('a')
-AVALUE = u('avalue')
-B = u('b')
-BVALUE = u('bvalue')
 
+NS = u'ns'
+FOO = u'foo'
+XXX = u'xxx'
+SPLAT = u'splat'
+SPLATV = u'splatv'
+A = u'a'
+AVALUE = u'avalue'
+B = u'b'
+BVALUE = u'bvalue'
 
+# pylint:disable=protected-access
 
 class ZopeXMLConfigurationErrorTests(unittest.TestCase):
 
@@ -96,8 +95,8 @@ def test___str___w_eline_ecolumn_dont_match_line_column_bad_file(self):
         pi = self._makeOne('/path/to/nonesuch.xml', 24, 32)
         pi.end(33, 21)
         self.assertEqual(str(pi),
-                        'File "/path/to/nonesuch.xml", line 24.32-33.21\n'
-                        '  Could not read source.')
+                         'File "/path/to/nonesuch.xml", line 24.32-33.21\n'
+                         '  Could not read source.')
 
     def test___str___w_good_file(self):
         pi = self._makeOne('tests//sample.zcml', 3, 2)
@@ -167,8 +166,8 @@ def test_startElementNS_w_ignore_depth_already_set(self):
     def test_startElementNS_context_begin_raises_wo_testing(self):
         from zope.configuration.xmlconfig import ZopeXMLConfigurationError
         class ErrorContext(FauxContext):
-          def begin(self, *args):
-            raise AttributeError("xxx")
+            def begin(self, *args):
+                raise AttributeError("xxx")
         context = ErrorContext()
         locator = FauxLocator('tests//sample.zcml', 1, 1)
         handler = self._makeOne(context)
@@ -187,8 +186,8 @@ def begin(self, *args):
 
     def test_startElementNS_context_begin_raises_w_testing(self):
         class ErrorContext(FauxContext):
-          def begin(self, *args):
-            raise AttributeError("xxx")
+            def begin(self, *args):
+                raise AttributeError("xxx")
         context = ErrorContext()
         locator = FauxLocator('tests//sample.zcml', 1, 1)
         handler = self._makeOne(context, True)
@@ -233,8 +232,8 @@ def test_endElementNS_w_ignore_depth_already_set(self):
     def test_endElementNS_context_end_raises_wo_testing(self):
         from zope.configuration.xmlconfig import ZopeXMLConfigurationError
         class ErrorContext(FauxContext):
-          def end(self):
-            raise AttributeError("xxx")
+            def end(self):
+                raise AttributeError("xxx")
         class Info(object):
             _line = _col = None
             def end(self, line, col):
@@ -254,8 +253,8 @@ def end(self, line, col):
 
     def test_endElementNS_context_end_raises_w_testing(self):
         class ErrorContext(FauxContext):
-          def end(self):
-            raise AttributeError("xxx")
+            def end(self):
+                raise AttributeError("xxx")
         class Info(object):
             _line = _col = None
             def end(self, line, col):
@@ -314,7 +313,7 @@ def test_evaluateCondition_w_installed_no_args(self):
         context = FauxContext()
         handler = self._makeOne(context)
         with self.assertRaises(ValueError) as exc:
-                handler.evaluateCondition('installed')
+            handler.evaluateCondition('installed')
         self.assertEqual(str(exc.exception.args[0]),
                          "Package name missing: 'installed'")
 
@@ -346,7 +345,7 @@ def test_evaluateCondition_w_not_installed_hit(self):
         context = FauxContext()
         handler = self._makeOne(context)
         self.assertTrue(
-                handler.evaluateCondition('not-installed nonsuch.package'))
+            handler.evaluateCondition('not-installed nonsuch.package'))
 
     def test_evaluateCondition_w_unknown_verb(self):
         context = FauxContext()
@@ -380,10 +379,11 @@ def _callFUT(self, *args, **kw):
         return processxmlfile(*args, **kw)
 
     def test_w_empty_xml(self):
+        from io import StringIO
         from zope.configuration.config import ConfigurationMachine
         from zope.configuration.xmlconfig import registerCommonDirectives
         from zope.configuration.xmlconfig import ZopeSAXParseException
-        from zope.configuration._compat import StringIO
+
         context = ConfigurationMachine()
         registerCommonDirectives(context)
         with self.assertRaises(ZopeSAXParseException) as exc:
@@ -395,21 +395,22 @@ def test_w_valid_xml_fp(self):
         # Integration test, really
         from zope.configuration.config import ConfigurationMachine
         from zope.configuration.xmlconfig import registerCommonDirectives
-        from zope.configuration._compat import b
         from zope.configuration.tests.samplepackage import foo
-        file = open(path("samplepackage", "configure.zcml"))
+
         context = ConfigurationMachine()
         registerCommonDirectives(context)
-        self._callFUT(file, context)
+
+        with open(path("samplepackage", "configure.zcml")) as file:
+            self._callFUT(file, context)
         self.assertEqual(foo.data, [])
         context.execute_actions()
         data = foo.data.pop()
-        self.assertEqual(data.args, (('x', b('blah')), ('y', 0)))
+        self.assertEqual(data.args, (('x', (b'blah')), ('y', 0)))
         self.assertEqual(clean_info_path(repr(data.info)),
-                'File "tests/samplepackage/configure.zcml", line 12.2-12.29')
+                         'File "tests/samplepackage/configure.zcml", line 12.2-12.29')
         self.assertEqual(clean_info_path(str(data.info)),
-                'File "tests/samplepackage/configure.zcml", line 12.2-12.29\n'
-                + '    <test:foo x="blah" y="0" />')
+                         'File "tests/samplepackage/configure.zcml", line 12.2-12.29\n'
+                         + '    <test:foo x="blah" y="0" />')
         self.assertEqual(data.package, None)
         self.assertEqual(data.basepath, None)
 
@@ -536,7 +537,6 @@ def test_w_files_passed_and_package(self):
         from zope.configuration import xmlconfig
         from zope.configuration.config import ConfigurationMachine
         from zope.configuration.xmlconfig import registerCommonDirectives
-        from zope.configuration._compat import b
         from zope.configuration.tests import samplepackage
         from zope.configuration.tests.samplepackage import foo
         context = ConfigurationMachine()
@@ -557,12 +557,12 @@ def test_w_files_passed_and_package(self):
         self.assertEqual(action['callable'], foo.data.append)
         self.assertEqual(action['includepath'], (fqn2,))
         self.assertIsInstance(action['args'][0], foo.stuff)
-        self.assertEqual(action['args'][0].args, (('x', b('foo')), ('y', 2)))
+        self.assertEqual(action['args'][0].args, (('x', (b'foo')), ('y', 2)))
         action = context.actions[1]
         self.assertEqual(action['callable'], foo.data.append)
         self.assertEqual(action['includepath'], (fqn3,))
         self.assertIsInstance(action['args'][0], foo.stuff)
-        self.assertEqual(action['args'][0].args, (('x', b('foo')), ('y', 3)))
+        self.assertEqual(action['args'][0].args, (('x', (b'foo')), ('y', 3)))
         self.assertEqual(context.stack, before_stack)
         self.assertEqual(len(context._seen_files), 3)
         self.assertIn(fqn1, context._seen_files)
@@ -698,7 +698,6 @@ def _callFUT(self, *args, **kw):
 
     def test_wo_execute_wo_context_wo_package(self):
         from zope.configuration import xmlconfig
-        from zope.configuration._compat import b
         from zope.configuration.tests.samplepackage import foo
         file_name = path("samplepackage", "configure.zcml")
         logger = LoggerStub()
@@ -710,12 +709,11 @@ def test_wo_execute_wo_context_wo_package(self):
         self.assertEqual(len(context.actions), 1)
         action = context.actions[0]
         self.assertEqual(action['discriminator'],
-                         (('x', b('blah')), ('y', 0)))
+                         (('x', (b'blah')), ('y', 0)))
         self.assertEqual(action['callable'], foo.data.append)
 
     def test_wo_execute_wo_context_w_package(self):
         from zope.configuration import xmlconfig
-        from zope.configuration._compat import b
         from zope.configuration.tests import samplepackage
         from zope.configuration.tests.samplepackage import foo
         file_name = path("samplepackage", "configure.zcml")
@@ -730,14 +728,13 @@ def test_wo_execute_wo_context_w_package(self):
         self.assertEqual(len(context.actions), 1)
         action = context.actions[0]
         self.assertEqual(action['discriminator'],
-                         (('x', b('blah')), ('y', 0)))
+                         (('x', (b'blah')), ('y', 0)))
         self.assertEqual(action['callable'], foo.data.append)
 
     def test_wo_execute_w_context(self):
         from zope.configuration import xmlconfig
         from zope.configuration.config import ConfigurationMachine
         from zope.configuration.xmlconfig import registerCommonDirectives
-        from zope.configuration._compat import b
         from zope.configuration.tests import samplepackage
         from zope.configuration.tests.samplepackage import foo
         context = ConfigurationMachine()
@@ -755,22 +752,21 @@ def test_wo_execute_w_context(self):
         self.assertEqual(len(context.actions), 1)
         action = context.actions[0]
         self.assertEqual(action['discriminator'],
-                         (('x', b('blah')), ('y', 0)))
+                         (('x', (b'blah')), ('y', 0)))
         self.assertEqual(action['callable'], foo.data.append)
 
     def test_w_execute(self):
         import os
         from zope.configuration import xmlconfig
-        from zope.configuration._compat import b
         from zope.configuration.tests.samplepackage import foo
         file_name = path("samplepackage", "configure.zcml")
         logger = LoggerStub()
         with _Monkey(xmlconfig, logger=logger):
-            context = self._callFUT(file_name)
+            self._callFUT(file_name)
         self.assertEqual(len(logger.debugs), 1)
         self.assertEqual(logger.debugs[0], ('include %s', (file_name,), {}))
         data = foo.data.pop()
-        self.assertEqual(data.args, (('x', b('blah')), ('y', 0)))
+        self.assertEqual(data.args, (('x', (b'blah')), ('y', 0)))
         self.assertTrue(
             data.info.file.endswith(
                 os.path.normpath('tests/samplepackage/configure.zcml')))
@@ -780,7 +776,7 @@ def test_w_execute(self):
         self.assertEqual(data.info.ecolumn, 29)
         self.assertEqual(data.package, None)
         self.assertTrue(data.basepath.endswith(
-                        os.path.normpath('tests/samplepackage')))
+            os.path.normpath('tests/samplepackage')))
 
 
 class Test_string(unittest.TestCase):
@@ -790,7 +786,6 @@ def _callFUT(self, *args, **kw):
         return string(*args, **kw)
 
     def test_wo_execute_wo_context(self):
-        from zope.configuration._compat import b
         from zope.configuration.tests.samplepackage import foo
         file_name = path("samplepackage", "configure.zcml")
         with open(file_name) as f:
@@ -800,13 +795,12 @@ def test_wo_execute_wo_context(self):
         self.assertEqual(len(context.actions), 1)
         action = context.actions[0]
         self.assertEqual(action['discriminator'],
-                         (('x', b('blah')), ('y', 0)))
+                         (('x', (b'blah')), ('y', 0)))
         self.assertEqual(action['callable'], foo.data.append)
 
     def test_wo_execute_w_context(self):
         from zope.configuration.config import ConfigurationMachine
         from zope.configuration.xmlconfig import registerCommonDirectives
-        from zope.configuration._compat import b
         from zope.configuration.tests.samplepackage import foo
         context = ConfigurationMachine()
         registerCommonDirectives(context)
@@ -819,18 +813,17 @@ def test_wo_execute_w_context(self):
         self.assertEqual(len(context.actions), 1)
         action = context.actions[0]
         self.assertEqual(action['discriminator'],
-                         (('x', b('blah')), ('y', 0)))
+                         (('x', (b'blah')), ('y', 0)))
         self.assertEqual(action['callable'], foo.data.append)
 
     def test_w_execute(self):
-        from zope.configuration._compat import b
         from zope.configuration.tests.samplepackage import foo
         file_name = path("samplepackage", "configure.zcml")
         with open(file_name) as f:
             xml = f.read()
-        context = self._callFUT(xml)
+        self._callFUT(xml)
         data = foo.data.pop()
-        self.assertEqual(data.args, (('x', b('blah')), ('y', 0)))
+        self.assertEqual(data.args, (('x', (b'blah')), ('y', 0)))
         self.assertTrue(data.info.file, '<string>')
         self.assertEqual(data.info.line, 12)
         self.assertEqual(data.info.column, 2)
@@ -864,7 +857,6 @@ def _makeOne(self, *args, **kw):
     def test_ctor_w_global_context_missing(self):
         import os
         from zope.configuration import xmlconfig
-        from zope.configuration._compat import b
         from zope.configuration.tests.samplepackage import foo
         here = os.path.dirname(__file__)
         path = os.path.join(here, "samplepackage", "configure.zcml")
@@ -878,12 +870,11 @@ def test_ctor_w_global_context_missing(self):
         self.assertEqual(len(xc.context.actions), 1)
         action = xc.context.actions[0]
         self.assertEqual(action['discriminator'],
-                         (('x', b('blah')), ('y', 0)))
+                         (('x', (b'blah')), ('y', 0)))
         self.assertEqual(action['callable'], foo.data.append)
 
     def test_ctor(self):
         from zope.configuration import xmlconfig
-        from zope.configuration._compat import b
         from zope.configuration.tests import samplepackage
         from zope.configuration.tests.samplepackage import foo
         fqn = _packageFile(samplepackage, 'configure.zcml')
@@ -896,12 +887,11 @@ def test_ctor(self):
         self.assertEqual(len(xc.context.actions), 1)
         action = xc.context.actions[0]
         self.assertEqual(action['discriminator'],
-                         (('x', b('blah')), ('y', 0)))
+                         (('x', (b'blah')), ('y', 0)))
         self.assertEqual(action['callable'], foo.data.append)
 
     def test_ctor_w_module(self):
         from zope.configuration import xmlconfig
-        from zope.configuration._compat import b
         from zope.configuration.tests.samplepackage import foo
         from zope.configuration.tests import samplepackage
         fqn = _packageFile(samplepackage, 'configure.zcml')
@@ -914,13 +904,12 @@ def test_ctor_w_module(self):
         self.assertEqual(len(xc.context.actions), 1)
         action = xc.context.actions[0]
         self.assertEqual(action['discriminator'],
-                         (('x', b('blah')), ('y', 0)))
+                         (('x', (b'blah')), ('y', 0)))
         self.assertEqual(action['callable'], foo.data.append)
 
     def test___call__(self):
         import os
         from zope.configuration import xmlconfig
-        from zope.configuration._compat import b
         from zope.configuration.tests import samplepackage
         from zope.configuration.tests.samplepackage import foo
         fqn = _packageFile(samplepackage, 'configure.zcml')
@@ -933,7 +922,7 @@ def test___call__(self):
         xc() # call to process the actions
         self.assertEqual(len(foo.data), 1)
         data = foo.data.pop(0)
-        self.assertEqual(data.args, (('x', b('blah')), ('y', 0)))
+        self.assertEqual(data.args, (('x', (b'blah')), ('y', 0)))
         self.assertTrue(
             data.info.file.endswith(
                 os.path.normpath('tests/samplepackage/configure.zcml')))
@@ -965,24 +954,23 @@ def _callFUT(self, *args, **kw):
     def test_wo_testing_passed(self):
         import os
         from zope.configuration import xmlconfig
-        from zope.configuration._compat import b
         from zope.configuration.tests import samplepackage
         from zope.configuration.tests.samplepackage import foo
         def _assertTestingFalse(func):
             def _wrapper(*args, **kw):
-                assert(not kw['testing'])
+                assert not kw['testing']
                 return func(*args, **kw)
             return _wrapper
         fqn = _packageFile(samplepackage, 'configure.zcml')
         context = xmlconfig._getContext()
         context.execute_actions = _assertTestingFalse(context.execute_actions)
         with _Monkey(xmlconfig,
-                        processxmlfile=_assertTestingFalse(
-                                                xmlconfig.processxmlfile)):
+                     processxmlfile=_assertTestingFalse(
+                         xmlconfig.processxmlfile)):
             self._callFUT(open(fqn), False)
         self.assertEqual(len(foo.data), 1)
         data = foo.data.pop(0)
-        self.assertEqual(data.args, (('x', b('blah')), ('y', 0)))
+        self.assertEqual(data.args, (('x', (b'blah')), ('y', 0)))
         self.assertTrue(
             data.info.file.endswith(
                 os.path.normpath('tests/samplepackage/configure.zcml')))
@@ -994,24 +982,23 @@ def _wrapper(*args, **kw):
     def test_w_testing_passed(self):
         import os
         from zope.configuration import xmlconfig
-        from zope.configuration._compat import b
         from zope.configuration.tests import samplepackage
         from zope.configuration.tests.samplepackage import foo
         def _assertTestingTrue(func):
             def _wrapper(*args, **kw):
-                assert(kw['testing'])
+                assert kw['testing']
                 return func(*args, **kw)
             return _wrapper
         fqn = _packageFile(samplepackage, 'configure.zcml')
         context = xmlconfig._getContext()
         context.execute_actions = _assertTestingTrue(context.execute_actions)
         with _Monkey(xmlconfig,
-                        processxmlfile=_assertTestingTrue(
-                                                xmlconfig.processxmlfile)):
+                     processxmlfile=_assertTestingTrue(
+                         xmlconfig.processxmlfile)):
             self._callFUT(open(fqn), True)
         self.assertEqual(len(foo.data), 1)
         data = foo.data.pop(0)
-        self.assertEqual(data.args, (('x', b('blah')), ('y', 0)))
+        self.assertEqual(data.args, (('x', (b'blah')), ('y', 0)))
         self.assertTrue(
             data.info.file.endswith(
                 os.path.normpath('tests/samplepackage/configure.zcml')))
@@ -1042,24 +1029,23 @@ def _callFUT(self, *args, **kw):
     def test_w_testing_passed(self):
         import os
         from zope.configuration import xmlconfig
-        from zope.configuration._compat import b
         from zope.configuration.tests import samplepackage
         from zope.configuration.tests.samplepackage import foo
         def _assertTestingTrue(func):
             def _wrapper(*args, **kw):
-                assert(kw['testing'])
+                assert kw['testing']
                 return func(*args, **kw)
             return _wrapper
         fqn = _packageFile(samplepackage, 'configure.zcml')
         context = xmlconfig._getContext()
         context.execute_actions = _assertTestingTrue(context.execute_actions)
         with _Monkey(xmlconfig,
-                        processxmlfile=_assertTestingTrue(
-                                                xmlconfig.processxmlfile)):
+                     processxmlfile=_assertTestingTrue(
+                         xmlconfig.processxmlfile)):
             self._callFUT(open(fqn))
         self.assertEqual(len(foo.data), 1)
         data = foo.data.pop(0)
-        self.assertEqual(data.args, (('x', b('blah')), ('y', 0)))
+        self.assertEqual(data.args, (('x', (b'blah')), ('y', 0)))
         self.assertTrue(
             data.info.file.endswith(
                 os.path.normpath('tests/samplepackage/configure.zcml')))
@@ -1119,12 +1105,13 @@ def clean_path(s):
 
 def clean_actions(actions):
     return [
-      {'discriminator': action['discriminator'],
-       'info': clean_info_path(repr(action['info'])),
-       'includepath': [clean_path(p) for p in action['includepath']],
-       }
-      for action in actions
-      ]
+        {
+            'discriminator': action['discriminator'],
+            'info': clean_info_path(repr(action['info'])),
+            'includepath': [clean_path(p) for p in action['includepath']],
+        }
+        for action in actions
+    ]
 
 def clean_text_w_paths(error):
     r = []
@@ -1158,7 +1145,7 @@ def __enter__(self):
             setattr(self.module, k, v)
 
     def __exit__(self, *exc_info):
-        for k, v in self.replacements.items():
+        for k in self.replacements:
             if k in self.orig:
                 setattr(self.module, k, self.orig[k])
             else: #pragma NO COVERSGE
diff --git a/src/zope/configuration/xmlconfig.py b/src/zope/configuration/xmlconfig.py
index 55d1aee..d33cd69 100644
--- a/src/zope/configuration/xmlconfig.py
+++ b/src/zope/configuration/xmlconfig.py
@@ -22,6 +22,7 @@
 import errno
 from glob import glob
 import logging
+import io
 import os
 import sys
 from xml.sax import make_parser
@@ -42,7 +43,6 @@
 from zope.configuration.fields import GlobalObject
 from zope.configuration.zopeconfigure import IZopeConfigure
 from zope.configuration.zopeconfigure import ZopeConfigure
-from zope.configuration._compat import StringIO
 from zope.configuration._compat import reraise
 
 logger = logging.getLogger("config")
@@ -326,9 +326,11 @@ class IInclude(Interface):
 
     file = NativeStringLine(
         title=u"Configuration file name",
-        description=(u"The name of a configuration file to be included/"
-                     u"excluded, relative to the directive containing the "
-                     u"including configuration file."),
+        description=(
+            u"The name of a configuration file to be included/"
+            u"excluded, relative to the directive containing the "
+            u"including configuration file."
+        ),
         required=False,
     )
 
@@ -510,7 +512,7 @@ def string(s, context=None, name="<string>", execute=True):
         context = ConfigurationMachine()
         registerCommonDirectives(context)
 
-    f = StringIO(s)
+    f = io.BytesIO(s) if isinstance(s, bytes) else io.StringIO(s)
     f.name = name
     processxmlfile(f, context)
 
diff --git a/src/zope/configuration/zopeconfigure.py b/src/zope/configuration/zopeconfigure.py
index 48ced1a..7204aeb 100644
--- a/src/zope/configuration/zopeconfigure.py
+++ b/src/zope/configuration/zopeconfigure.py
@@ -105,7 +105,7 @@
 
 from zope.configuration.config import GroupingContextDecorator
 from zope.configuration.fields import GlobalObject
-from zope.configuration._compat import u
+
 
 class IZopeConfigure(Interface):
     """The ``zope:configure`` Directive
@@ -117,24 +117,29 @@ class IZopeConfigure(Interface):
     information collected is used by subdirectives.
 
     It may seem that this directive can only be used once per file, but it can
-    be applied whereever it is convenient. 
+    be applied whereever it is convenient.
     """
 
     package = GlobalObject(
-        title=u("Package"),
-        description=u("The package to be used for evaluating relative imports "
-                      "and file names."),
+        title=u"Package",
+        description=(
+            u"The package to be used for evaluating relative imports "
+            u"and file names."
+        ),
         required=False)
 
     i18n_domain = BytesLine(
-        title=u("Internationalization domain"),
-        description=u("This is a name for the software project. It must be a "
-                      "legal file-system name as it will be used to contruct "
-                      "names for directories containing translation data. "
-                      "\n"
-                      "The domain defines a namespace for the message ids "
-                      "used by a project."),
-        required=False)
+        title=u"Internationalization domain",
+        description=(
+            u"This is a name for the software project. It must be a "
+            u"legal file-system name as it will be used to contruct "
+            u"names for directories containing translation data. "
+            u"\n"
+            u"The domain defines a namespace for the message ids "
+            u"used by a project."
+        ),
+        required=False
+    )
 
 
 class ZopeConfigure(GroupingContextDecorator):
@@ -146,4 +151,3 @@ def __init__(self, context, **kw):
             # if we have a package, we want to also define basepath
             # so we don't acquire one
             self.basepath = os.path.dirname(self.package.__file__)
-