docs: def getValueFromValue(value):
      """
      Extract the currently set field from a Value structure
      """
      if type(value) != common.AttributeValue:
          raise TypeError(
              "Expected an AttributeValue, but got {}".format(type(value)))
      if value.WhichOneof("value") is None:
          raise AttributeError("Nothing set for {}".format(value))
      return getattr(value, value.WhichOneof("value"))