class_docstr: Simple wrapper around a Python dict that exposes get/list_fields to emulate
  a "proxy" object entirely from Python.
code: def __contains__(self, key):
      return self.state.__contains__(key)
  
imports: from __future__ import print_function
  from __future__ import division
  from __future__ import absolute_import
  import turicreate
  import turicreate._connect.main
  from turicreate.data_structures.sframe import SFrame
  import turicreate.extensions
  from turicreate.extensions import _wrap_function_return
  from turicreate.toolkits._internal_utils import _toolkit_serialize_summary_struct
  from turicreate.util import _make_internal_url
  from turicreate.toolkits._main import ToolkitError
  from turicreate._deps.minimal_package import _minimal_package_import_check
  import turicreate.util._file_util
  import os
  from copy import copy
  import six
  import warnings
label_desc: Use image node_id 5 for calling the PythonProxy obj's underlying member method code with example usage: obj.__contains__(key) and returns: self