<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def refresh(self):
 """ Refresh this model from the server. Updates attributes with the server-defined values. This is useful where the Model instance came from a partial response (eg. a list query) and additional details are required. Existing attribute values will be overwritten. """

        r = self._client.request('GET', self.url)
        return self._deserialize(r.json(), self._manager)