Creates an AdWordsClient with information stored in a yaml string.

    Args:
      yaml_doc: The yaml string containing the cached AdWords data.

    Returns:
      An AdWordsClient initialized with the values cached in the string.

    Raises:
      A GoogleAdsValueError if the given yaml string does not contain the
      information necessary to instantiate a client object - either a
      required key was missing or an OAuth2 key was missing.

def LoadFromString(cls, yaml_doc):
    """Creates an AdWordsClient with information stored in a yaml string.

    Args:
      yaml_doc: The yaml string containing the cached AdWords data.

    Returns:
      An AdWordsClient initialized with the values cached in the string.

    Raises:
      A GoogleAdsValueError if the given yaml string does not contain the
      information necessary to instantiate a client object - either a
      required key was missing or an OAuth2 key was missing.
    """
    return cls(**googleads.common.LoadFromString(
        yaml_doc, cls._YAML_KEY, cls._REQUIRED_INIT_VALUES,
        cls._OPTIONAL_INIT_VALUES))