code: def post(self, url, body=None):
          
          response = self.http_request(url, 'POST', body or self, {'Content-Type': 'application/xml; charset=utf-8'})
          if response.status not in (200, 201, 204):
              self.raise_http_error(response)
  
          self._url = response.getheader('Location')
  
          if response.status in (200, 201):
              response_xml = response.read()
              logging.getLogger('recurly.http.response').debug(response_xml)
              self.update_from_element(ElementTree.fromstring(response_xml))
docs: Sends this `Resource` instance to the service with a
          ``POST`` request to the given URL. Takes an optional body