'Adds an insufficient_data action, represented as an SNS topic, to
this alarm. What to do when the insufficient_data state is reached.
:type action_arn: str
:param action_arn: SNS topics to which notification should be
sent if the alarm goes to state INSUFFICIENT_DATA.'

def add_insufficient_data_action(self, action_arn=None):

    if (not action_arn):
        return
    self.actions_enabled = 'true'
    self.insufficient_data_actions.append(action_arn)
