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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 make_retrigger_request(repo_name, request_id, auth, count=DEFAULT_COUNT_NUM, priority=DEFAULT_PRIORITY, dry_run=True):
 """ Retrigger a request using buildapi self-serve. Returns a request. Buildapi documentation: POST /self-serve/{branch}/request Rebuild `request_id`, which must be passed in as a POST parameter. `priority` and `count` are also accepted as optional parameters. `count` defaults to 1, and represents the number of times this build will be rebuilt. """

    url = '{}/{}/request'.format(SELF_SERVE, repo_name)
    payload = {'request_id': request_id}

    if count != DEFAULT_COUNT_NUM or priority != DEFAULT_PRIORITY:
        payload.update({'count': count,
                        'priority': priority})

    if dry_run:
        LOG.info('We would make a POST request to %s with the payload: %s' % (url, str(payload)))
        return None

    LOG.info("We're going to re-trigger an existing completed job with request_id: %s %i time(s)."
             % (request_id, count))
    req = requests.post(
        url,
        headers={'Accept': 'application/json'},
        data=payload,
        auth=auth,
        timeout=TCP_TIMEOUT,
    )
    # TODO: add debug message with job_id URL.
    return req