'Sends the error response to the remote client, possibly resolving a
custom error response body based on x-container-meta-web-error.
:param response: The error response we should default to sending.
:param env: The original request WSGI environment.
:param start_response: The WSGI start_response hook.'

def _error_response(self, response, env, start_response):

    if (not self._error):
        start_response(self._response_status, self._response_headers, self._response_exc_info)
        return response
    save_response_status = self._response_status
    save_response_headers = self._response_headers
    save_response_exc_info = self._response_exc_info
    resp = self._app_call(make_env(env, 'GET', ('/%s/%s/%s/%s%s' % (self.version, self.account, self.container, self._get_status_int(), self._error)), self.agent, swift_source='SW'))
    if is_success(self._get_status_int()):
        start_response(save_response_status, self._response_headers, self._response_exc_info)
        return resp
    start_response(save_response_status, save_response_headers, save_response_exc_info)
    return response
