static CppCompositeType createI1_struct64(VxtManager vxtManager, CppCompositeType G1_struct,
			CppCompositeType H_struct, CppCompositeType C_struct, CppCompositeType E_struct) {
		try {
			CppCompositeType I1_struct = createStruct64("I1", 48);
			I1_struct.addDirectBaseClass(G1_struct.getComposite(), G1_struct, 0);
			I1_struct.addDirectBaseClass(H_struct.getComposite(), H_struct, 16);
			I1_struct.addIndirectVirtualBaseClass(C_struct.getComposite(), C_struct, 0,
				ClassUtils.VXPTR_TYPE,
				1);
			I1_struct.addIndirectVirtualBaseClass(E_struct.getComposite(), E_struct, 0,
				ClassUtils.VXPTR_TYPE,
				2);
			I1_struct.addMember("i11", intT, false, 32);
			return I1_struct;
		}
		catch (Exception e) {
			String msg = "Error in static initialization of test: " + e;
			Msg.error(null, msg);
			throw new AssertException(msg);
		}
	}
This is not part of the DataTypeManager API... it is only for testing when needing
 to clear results because of another run that creates the same-named types
Ghidra/Features/PDB/src/test/java/ghidra/app/util/pdb/pdbapplicator/CppCompositeTypeTest.java