private void getAddressSet(Group group, AddressSet set) {
		if (group instanceof ProgramFragment) {
			set.add((ProgramFragment) group);
		}
		else {
			Group[] groups = ((ProgramModule) group).getChildren();
			for (Group group2 : groups) {
				getAddressSet(group2, set);
			}
		}
	}
Get the address set for the given group. If group is a Module, then
recursively call this method for all descendants.
@param group either a Fragment or a Module
@param set address set to populate
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/programtree/TreeViewProvider.java