diff --git a/grammars/python.cson b/grammars/python.cson
index 35a11ca..c50bafb 100644
--- a/grammars/python.cson
+++ b/grammars/python.cson
@@ -289,7 +289,7 @@
                 'name': 'variable.parameter.function.python'
               '2':
                 'name': 'punctuation.separator.parameters.python'
-            'match': '\\b([a-zA-Z_][a-zA-Z_0-9]*)\\s*(?:(,)|(?=[\\n\\)]))'
+            'match': '\\b([a-zA-Z_][a-zA-Z_0-9]*)\\s*(?:(,)|\\:\\s*\\w*(,*))'
           }
         ]
       }