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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def process_queue(queue, quantity=1, backend='sqlite', is_runner=False):
    '''
    Pop items off a queue and create an event on the Salt event bus to be
    processed by a Reactor.

    CLI Example:

    .. code-block:: bash

        salt-run queue.process_queue myqueue
        salt-run queue.process_queue myqueue 6
        salt-run queue.process_queue myqueue all backend=sqlite
    '''
    # get ready to send an event
    event = get_event(
                'master',
                __opts__['sock_dir'],
                __opts__['transport'],
                opts=__opts__,
                listen=False)
    try:
        items = pop(queue=queue, quantity=quantity, backend=backend, is_runner=is_runner)
    except SaltInvocationError as exc:
        error_txt = '{0}'.format(exc)
        __jid_event__.fire_event({'errors': error_txt}, 'progress')
        return False

    data = {'items': items,
            'backend': backend,
            'queue': queue,
            }
    event.fire_event(data, tagify([queue, 'process'], prefix='queue'))
    return data