docs: def _retry_until_powered_on(self, power):
          """This method retries power on operation.
  
          :param: power : target power state
          """
          # If the system is in the same power state as
          # requested by the user, it gives the error
          # InvalidOperationForSystemState. To avoid this error
          # the power state is checked before power on
          # operation is performed.
          status = self.get_host_power_status()
          if (status != power):
              self._perform_power_op(POWER_STATE[power])
              return self.get_host_power_status()
          else:
              return status