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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 _trigger_job(job):
 """ trigger a job """

    if job.api_instance().is_running():
        return "{0}, {1} is already running".format(job.host, job.name)
    else:
        requests.get(job.api_instance().get_build_triggerurl())
        return "triggering {0}, {1}...".format(job.host, job.name)