class_docstr: A dictionary that lazily load its values when they are requested.
class_docstr_tok: ["A","dictionary","that","lazily","load","its","values","when","they","are","requested","."]
code: def __contains__(self, item):
      return item in self._mapping
  
imports: import importlib
  import re
  from collections import OrderedDict
  from typing import List, Union
  from fastNLP.transformers.torch.configuration_utils import PretrainedConfig
  from fastNLP.transformers.torch.file_utils import CONFIG_NAME
  from fastNLP.core.log import logger
label_desc: Use image node_id 7 for calling the _LazyConfigMapping obj's underlying member method code with example usage: obj.__contains__(item) and returns: unknown