Remove the use of callable() in re to silence warnings under -3.

Lib/re.py

@@ -316,7 +316,7 @@ class Scanner:
             if i == j:
                 break
             action = self.lexicon[m.lastindex-1][1]
-            if callable(action):
+            if hasattr(action, '__call__'):
                 self.match = m
                 action = action(self, m.group())
             if action is not None: