code: def time_replacer(match, timestamp):
          
          # match.group(0) = entire match
          # match.group(1) = match in braces #1
          return time.strftime(match.group(1), time.gmtime(timestamp))
docs: Transforms the timestamp to the format the regex match determines.
  
          :param str match: the regex match
          :param time timestamp: the timestamp to format with match.group(1)
          :return str: the timestamp formated with strftime the way the
                       regex-match within the first set of braces defines