diff --git a/pep8.py b/pep8.py
index c22e63ee..b1916cce 100755
--- a/pep8.py
+++ b/pep8.py
@@ -1316,7 +1316,10 @@ def _is_eol_token(token, _eol_token=_is_eol_token):
 
 def _get_parameters(function):
     if sys.version_info >= (3, 3):
-        return list(inspect.signature(function).parameters)
+        return [parameter.name
+                for parameter
+                in inspect.signature(function).parameters.values()
+                if parameter.kind == parameter.POSITIONAL_OR_KEYWORD]
     else:
         return inspect.getargspec(function)[0]