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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 remove_timezone(cls, timestr):
 """Completely remove timezone information, if any. :return: the new string if timezone was found, `None` otherwise """

        if re.match(r".*[\-+]?\d{2}:\d{2}$", timestr):
            return re.sub(
                r"(.*)(\s[\+-]?\d\d:\d\d)$",
                r"\1",
                timestr
            )