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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 _call(self, method, url, params, uploads):
 """ Initiate resquest to server and handle outcomes. """

        try:
            data = self._request(method, url, params, uploads)
        except Exception, e:
            self._failed_cb(e)
        else:
            self._completed_cb(data)