wraps response_from for timeseries calls, returns the resulting dict

def _construct_timeseries(self, timeseries, constraints={}):
        """
        wraps response_from for timeseries calls, returns the resulting dict
        """
        self.response_from(timeseries, constraints)
        if self.response == None:
            return None
        return {'data':self.response['data'],
                'period':self.response['period'],
                'start time':datetime.datetime.fromtimestamp(self.response['start_time']),
                'end time':datetime.datetime.fromtimestamp(self.response['end_time'])}