Roll back some of the changes as per review comments

setup.cfg

@@ -11,3 +11,8 @@ docs = easy_install zope.exceptions[docs]
 
 [bdist_wheel]
 universal = 1
+
+[flake8]
+extend-ignore = F401
+# https://pep8.readthedocs.org/en/latest/intro.html#error-codes
+# F401: ``module`` imported but unused

src/zope/exceptions/__init__.py

@@ -17,32 +17,26 @@
 application-specific packages.
 """
 
-from zope.exceptions.interfaces import (  # noqa: F401
-    DuplicationError,
-    IDuplicationError,
-    UserError,
-    IUserError,
-)
+from zope.exceptions.interfaces import DuplicationError
+from zope.exceptions.interfaces import IDuplicationError
+from zope.exceptions.interfaces import UserError
+from zope.exceptions.interfaces import IUserError
 
-from zope.exceptions.exceptionformatter import (  # noqa: F401
-    format_exception,
-    print_exception,
-    extract_stack,
-)
+from zope.exceptions.exceptionformatter import format_exception
+from zope.exceptions.exceptionformatter import print_exception
+from zope.exceptions.exceptionformatter import extract_stack
 
 # avoid dependency on zope.security:
 try:
-    import zope.security  # noqa: F401
+    import zope.security
 except ImportError as v:  # pragma: no cover
     # "ImportError: No module named security"
     if 'security' not in str(v):
         raise
 else:  # pragma: no cover
-    from zope.security.interfaces import (  # noqa: F401
-        IUnauthorized,
-        Unauthorized,
-        IForbidden,
-        IForbiddenAttribute,
-        Forbidden,
-        ForbiddenAttribute,
-    )
+    from zope.security.interfaces import IUnauthorized
+    from zope.security.interfaces import Unauthorized
+    from zope.security.interfaces import IForbidden
+    from zope.security.interfaces import IForbiddenAttribute
+    from zope.security.interfaces import Forbidden
+    from zope.security.interfaces import ForbiddenAttribute

src/zope/exceptions/exceptionformatter.py

@@ -175,7 +175,7 @@ def formatLastLine(self, exc_line):
 
     def formatException(self, etype, value, tb):
         # The next line provides a way to detect recursion.
-        __exception_formatter__ = 1  # noqa: F841
+        __exception_formatter__ = 1  # noqa
         result = []
         while tb is not None:
             if tb.tb_frame.f_locals.get('__exception_formatter__'):
@@ -207,7 +207,7 @@ def extractStack(self, f=None):
                 f = sys.exc_info()[2].tb_frame.f_back
 
         # The next line provides a way to detect recursion.
-        __exception_formatter__ = 1  # noqa: F841
+        __exception_formatter__ = 1  # noqa
         result = []
         while f is not None:
             if f.f_locals.get('__exception_formatter__'):