message: Actually restrict parse_expression to expression nodes.
diff: @@ -117,7 +117,7 @@ def parse_expression(src):
  """
  node = parse_str(src)
  assert isinstance(node, gast.Module)
  - if len(node.body) != 1 and not isinstance(node.body[0], gast.Expr):
  + if len(node.body) != 1 or not isinstance(node.body[0], gast.Expr):
  raise ValueError(
  'Expected a single expression, found instead %s' % node.body)
  return node.body[0].value
  