python 3.5 uses atom_expr node in many places where previous python would use power node

jedi/evaluate/__init__.py

@@ -291,7 +291,7 @@ class Evaluator(object):
             types = set([element])  # TODO this is no real evaluation.
         elif element.type == 'expr_stmt':
             types = self.eval_statement(element)
-        elif element.type == 'power':
+        elif element.type == 'power' or element.type == 'atom_expr':
             types = self._eval_atom(element.children[0])
             for trailer in element.children[1:]:
                 if trailer == '**':  # has a power operation.