code: def __missing__(self, key):
      if self.default_factory is None:
          raise KeyError(key)
      self[key] = value = self.default_factory()
      return value
  
file_path: Theano/theano/compat/__init__.py
imports: from __future__ import absolute_import, print_function, division
  from six import PY3, b, BytesIO, next
  from six.moves import configparser
  from six.moves import reload_module
  from collections import OrderedDict
label_desc: Use image node_id 3 for calling the DefaultOrderedDict obj's underlying member method code with example usage: obj.__missing__(key) and returns: value