Think this closes #10 and adds Python 3 support?

moment/date.py

@@ -5,6 +5,12 @@
 import calendar
 from datetime import datetime, timedelta
 
+from .utils import _iteritems
+
+
+# ----------------------------------------------------------------------------
+# Utilities
+# ----------------------------------------------------------------------------
 
 def add_month(date, number):
     """Add a number of months to a date."""
@@ -26,6 +32,10 @@ def update_month(date, month):
     return date.replace(year=year, month=month, day=day)
 
 
+# ----------------------------------------------------------------------------
+# Main functionality
+# ----------------------------------------------------------------------------
+
 class MutableDate(object):
     """Incapsulate mutable dates in one class."""
 
@@ -35,7 +45,7 @@ def __init__(self, date):
     def add(self, key=None, amount=None, **kwds):
         """Add time to the original moment."""
         if not key and not amount and len(kwds):
-            for k, v in kwds.iteritems():
+            for k, v in _iteritems(kwds):
                 self.add(k, v)
         if key == 'years' or key == 'year':
             self._date = add_month(self._date, amount * 12)
@@ -64,7 +74,7 @@ def sub(self, key=None, amount=None, **kwds):
     def subtract(self, key=None, amount=None, **kwds):
         """Subtract time from the original moment."""
         if not key and not amount and len(kwds):
-            for k, v in kwds.iteritems():
+            for k, v in _iteritems(kwds):
                 self.subtract(k, v)
         if key == 'years' or key == 'year':
             self._date = subtract_month(self._date, amount * 12)
@@ -88,7 +98,7 @@ def subtract(self, key=None, amount=None, **kwds):
 
     def replace(self, **kwds):
         """A Pythonic way to replace various date attributes."""
-        for key, value in kwds.iteritems():
+        for key, value in _iteritems(kwds):
             if key == 'years' or key == 'year':
                 self._date = self._date.replace(year=value)
             elif key == 'months' or key == 'month':

moment/parse.py

@@ -1,4 +1,5 @@
 from datetime import datetime
+from .utils import STRING_TYPES
 
 
 def parse_date_and_formula(*args):
@@ -13,7 +14,7 @@ def parse_date_and_formula(*args):
             # Python datetime needs the month and day, too.
             date = [date[0], 1, 1]
         date = datetime(*date)
-    elif isinstance(date, str) or isinstance(date, unicode):
+    elif isinstance(date, STRING_TYPES):
         if formula is None:
             formula = "%Y-%m-%d"
         date = datetime.strptime(date, formula)

moment/utils.py

@@ -0,0 +1,16 @@
+"""
+Added for Python 3 compatibility.
+"""
+
+import sys
+
+
+STRING_TYPES = (basestring, ) if sys.version_info < (3, 0) else (str, )
+
+
+def _iteritems(data):
+    "For Python 3 support."
+    if sys.version_info < (3, 0):
+        return data.iteritems()
+    else:
+        return data.items()