Pops a task off the queue.

        :param queue_name: The name of the queue. Usually handled by the
            ``Gator`` instance.
        :type queue_name: string

        :returns: The data for the task.
        :rtype: string

def pop(self, queue_name):
        """
        Pops a task off the queue.

        :param queue_name: The name of the queue. Usually handled by the
            ``Gator`` instance.
        :type queue_name: string

        :returns: The data for the task.
        :rtype: string
        """
        cls = self.__class__
        queue = cls.queues.get(queue_name, [])

        if queue:
            task_id = queue.pop(0)
            return cls.task_data.pop(task_id, None)