code: def sdc(self):
          
          self.connection._check_login()
          response = self.connection._do_get("{}/{}".format(self.connection._api_url, "types/Sdc/instances")).json()       
          all_sdc = []
          for sdc in response:
              all_sdc.append(
                  SIO_SDC.from_dict(sdc)
              )
          return all_sdc
docs: Returns a `list` of all the `ScaleIO_SDC` known to the cluster.  Updates every time - no caching.
          :return: a `list` of all the `ScaleIO_SDC` known to the cluster.
          :rtype: list