Noop methods don't work in the hierarchical domain.

[sebastianstock]

It seems that the methods without subtasks don't seem to work for in the hierarchical domain.

For example, when giving the task move_item mobipick klt_3 table_3 at the beginning of the demo (where the robot initially knows that klt_3 is on table_3) it does not find a plan.

The same problem occurs when first doing a get_item mobipick multimeter_1 and then giving the same task again, it does not find a plan. For both cases there are noop-methods in the hierarchical domain. But for some reason they are not applied.

[sebastianstock]

It turned out that the noop methods and the hierarchical domain work fine. However, solve_problemmethods of hierarchical domain returns None if the resulting plan is empty which in turn leads to the printout in the task server node and result in the task_server that no plan could be found.