@classmethod<EOL><INDENT>def remove_parenthesis_around_tz(cls, timestr):<DEDENT>
parenthesis = cls.TIMEZONE_PARENTHESIS.match(timestr)<EOL>if parenthesis is not None:<EOL><INDENT>return parenthesis.group(<NUM_LIT:1>)<EOL><DEDENT>
get rid of parenthesis around timezone: (GMT) => GMT

        :return: the new string if parenthesis were found, `None` otherwise