accept unicode strings in parse_string() under Python 2

bitmath/__init__.py

@@ -79,6 +79,7 @@
 # Python 3.x compat
 if sys.version > '3':
     long = int  # pragma: PY2X no cover
+    unicode = str  # pragma: PY2X no cover
 
 #: A list of all the valid prefix unit types. Mostly for reference,
 #: also used by the CLI tool as valid types
@@ -1331,13 +1332,13 @@ def parse_string(s):
 the unit.
     """
     # Strings only please
-    if type(s) is not str:
+    if type(s) is not str and type(s) is not unicode:
         raise ValueError("parse_string only accepts string inputs but a %s was given" %
                          type(s))
 
     # get the index of the first alphabetic character
     try:
-        index = list(map(str.isalpha, s)).index(True)
+        index = list([i.isalpha() for i in s]).index(True)
     except ValueError:
         # If there's no alphabetic characters we won't be able to .index(True)
         raise ValueError("No unit detected, can not parse string '%s' into a bitmath object" % s)

tests/test_parse.py

@@ -81,3 +81,9 @@ def test_parse_string_non_string_input(self):
         """parse_string can identify a non-string input"""
         with self.assertRaises(ValueError):
             bitmath.parse_string(12345)
+
+    def test_parse_string_unicode(self):
+        """parse_string can handle a unicode string"""
+        self.assertEqual(
+            bitmath.parse_string(u"750 GiB"),
+            bitmath.GiB(750))