DRY x0ret's code a little bit.

uncompyle6/semantics/customize26_27.py

@@ -31,28 +31,31 @@ def customize_for_version26_27(self, version):
     if version > 2.6:
         TABLE_DIRECT.update({
             'except_cond2':	( '%|except %c as %c:\n', 1, 5 ),
+            # When a generator is a single parameter of a function,
+            # it doesn't need the surrounding parenethesis.
+            'generator_no_parens': ('%c%P', 0, (1, -1, ', ', 100)),
         })
     else:
         TABLE_DIRECT.update({
             'testtrue_then': ( 'not %p', (0, 22) ),
-
         })
 
     def n_call(node):
         mapping = self._get_mapping(node)
-        table = mapping[0]
         key = node
         for i in mapping[1:]:
             key = key[i]
             pass
         if key.kind == 'CALL_FUNCTION_1':
+            # A function with one argument. If this is a generator,
+            # no parenthesis is needed.
             args_node = node[-2]
             if args_node == 'expr':
                 n = args_node[0]
                 if n == 'generator_exp':
-                    template = ('%c%P', 0, (1, -1, ', ', 100))
-                    self.template_engine(template, node)
-                    self.prune()
+                    node.kind = 'generator_no_parens'
+                    pass
+                pass
 
         self.default(node)
     self.n_call = n_call