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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 _requestresponse(self, method, url, body=None, headers={}):
 """Internal method to perform request and verify reponse. @param method: name of the method to use (e.g. 'GET') @param url : remote URL to query @type method: L{str} @type url : L{str} @returns: L{str} response from server query @raises RuntimeError: if query is unsuccessful """

        try:
            self.request(method, url)
            response = self.getresponse()
        except Exception,e:
            raise RuntimeError("Unable to query server %s: %s\n\n"
                               "Perhaps you need a valid proxy credential?\n"
                               % (self.host, e))
        if response.status != 200:
            raise RuntimeError("Server returned code %d: %s%s"
                               % (response.status, response.reason,
                                  response.read()))
        return response