Use inspect.getfullargspec() in Python3 (#110)

Select argspec based on python version

Author: riconnon

validators/utils.py

@@ -37,10 +37,15 @@ def func_args_as_dict(func, args, kwargs):
     Return given function's positional and key value arguments as an ordered
     dictionary.
     """
+    if six.PY2:
+        _getargspec = inspect.getargspec
+    else:
+        _getargspec = inspect.getfullargspec
+
     arg_names = list(
         OrderedDict.fromkeys(
             itertools.chain(
-                inspect.getargspec(func)[0],
+                _getargspec(func)[0],
                 kwargs.keys()
             )
         )