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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_job_id(job_id, prefix=None):
 """Construct an ID for a new job. :type job_id: str or ``NoneType`` :param job_id: the user-provided job ID :type prefix: str or ``NoneType`` :param prefix: (Optional) the user-provided prefix for a job ID :rtype: str :returns: A job ID """

    if job_id is not None:
        return job_id
    elif prefix is not None:
        return str(prefix) + str(uuid.uuid4())
    else:
        return str(uuid.uuid4())