code: def get_asset_temporal_assignment_session(self):
          
          if not self.supports_asset_temporal_assignment():
              raise Unimplemented()
          try:
              from . import sessions
          except ImportError:
              raise  # OperationFailed()
          try:
              session = sessions.AssetTemporalAssignmentSession(proxy=self._proxy,
                                                                runtime=self._runtime)
          except AttributeError:
              raise  # OperationFailed()
          return session
docs: Gets the session for assigning temporal coverage to an asset.
  
          return: (osid.repository.AssetTemporalAssignmentSession) - an
                  AssetTemporalAssignmentSession
          raise:  OperationFailed - unable to complete request
          raise:  Unimplemented - supports_asset_temporal_assignment() is
                  false
          compliance: optional - This method must be implemented if
                      supports_asset_temporal_assignment() is true.