Get action type.
        :param action:
        :return:

def _get_action_type(self, action):
        '''
        Get action type.
        :param action:
        :return:
        '''
        action_name = next(iter(action or {'': None}))
        if ':' not in action_name:
            action_name = '{}:{}'.format(self.CALL_TYPE, action_name)

        return action_name.split(':')[0] or None