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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 create_run_logfile(folder):
 """Create a 'run.log' within folder. This file contains the time of the latest successful run. """

    with open(os.path.join(folder, "run.log"), "w") as f:
        datestring = datetime.datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S")
        f.write("timestamp: '%s'" % datestring)