code: def custom(self, payload):
          
          url = "{url_base}/resource/{pid}/scimeta/custom/".format(url_base=self.hs.url_base,
                                                                   pid=self.pid)
          r = self.hs._request('POST', url, data=payload)
          return r
docs: :param payload:
              a key/value object containing the scimeta you want to store
              e.g. {"weather": "sunny", "temperature": "80C" }
          :return:
              empty (200 status code)