def response_as_single(self, copy=0):
        """ convert the response map to a single data frame with Multi-Index columns """
        arr = []
        for sid, frame in self.response.iteritems():
            if copy:
                frame = frame.copy()
            'security' not in frame and frame.insert(0, 'security', sid)
            arr.append(frame.reset_index().set_index(['date', 'security']))
        return concat(arr).unstack()
convert the response map to a single data frame with Multi-Index columns