code: def remove_timezone(cls, timestr):
          
          if re.match(r".*[\-+]?\d{2}:\d{2}$", timestr):
              return re.sub(
                  r"(.*)(\s[\+-]?\d\d:\d\d)$",
                  r"\1",
                  timestr
              )
docs: Completely remove timezone information, if any.
  
          :return: the new string if timezone was found, `None` otherwise