'Returns the estimated number of activity tasks in the
specified task list. The count returned is an approximation
and is not guaranteed to be exact. If you specify a task list
that no activity task was ever scheduled in then 0 will be
returned.
:type domain: string
:param domain: The name of the domain that contains the task list.
:type task_list: string
:param task_list: The name of the task list.
:raises: UnknownResourceFault, SWFOperationNotPermittedError'

def count_pending_activity_tasks(self, domain, task_list):

    return self.json_request('CountPendingActivityTasks', {'domain': domain, 'taskList': {'name': task_list}})
