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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 get_cookie_string(cls, url, user_agent=None, **kwargs):
 """ Convenience function for building a Cookie HTTP header value. """

        tokens, user_agent = cls.get_tokens(url, user_agent=user_agent, **kwargs)
        return "; ".join("=".join(pair) for pair in tokens.items()), user_agent