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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 DeleteOldCronJobRuns(self, cutoff_timestamp, cursor=None):
 """Deletes cron job runs that are older then the given timestamp."""

    query = "DELETE FROM cron_job_runs WHERE write_time < FROM_UNIXTIME(%s)"
    cursor.execute(query,
                   [mysql_utils.RDFDatetimeToTimestamp(cutoff_timestamp)])