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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 generate_token(self, username):
 """ assumes user exists in htpasswd file. Return the token for the given user by signing a token of the username and a hash of the htpasswd string. """

        serializer = self.get_signature()
        return serializer.dumps(
            {
                'username': username,
                'hashhash': self.get_hashhash(username)
            }
        ).decode('UTF-8')