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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 unwatch(self, username):
 """Unwatch a user :param username: The username you want to unwatch """


        if self.standard_grant_type is not "authorization_code":
            raise DeviantartError("Authentication through Authorization Code (Grant Type) is required in order to connect to this endpoint.")

        response = self._req('/user/friends/unwatch/{}'.format(username))

        return response['success']