Fetch the validation code used by a para, making the given OccupiedCoreAssumption.
OccupiedCoreAssumption
Returns None if either the para is not registered or the assumption is Freed and the para already occupies a core.
None
Freed
Fetch the validation code used by a para, making the given
OccupiedCoreAssumption.Returns
Noneif either the para is not registered or the assumption isFreedand the para already occupies a core.