code: def __contains__(self, m):
      return m in self.d
  
imports: import contextlib
  import sys
  import types
  import pytest
  import env
  from pybind11_tests import detailed_error_messages_enabled
  from pybind11_tests import pytypes
label_desc: Use image node_id 1 for calling the CustomContains obj's underlying member method code with example usage: obj.__contains__(m) and returns: unknown