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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 post_swagger(self):
 """ List of post-swagger methods from registered middleware. This is used to modify documentation (eg add/remove any extra information, provided by the middleware) """

        middleware = sort_by_priority(self)
        return tuple(m.post_swagger for m in middleware if hasattr(m, 'post_swagger'))