def __getitem__(self, key):
    try:
      return self._values[key]
    except __HOLE__:
      key = self._key_checker.CheckValue(key)
      val = self._value_checker.DefaultValue()
      self._values[key] = val
      return val
dataset/ETHPy150Open sklearn-theano/sklearn-theano/sklearn_theano/externals/google/protobuf/internal/containers.py/ScalarMap.__getitem__