@Override
			public void modifyPrivate(ProgramDB program) {
				try {
					Parameter my_count =
						new ParameterImpl("count", new IntegerDataType(), 4, program);

					// 0x0100194b	"undefined FUN_0100194b(undefined4 param_1, undefined4 param_2)"
					// 0x0100299e	"undefined FUN_0100299e(undefined4 param_1, undefined4 param_2, undefined param_3)"
					// 0x01004132	"undefined FUN_01004132(undefined4 param_1, undefined4 param_2, undefined4 param_3)"
					// 0x01004a15	"undefined FUN_01004a15(undefined4 param_1, undefined4 param_2)"
					Function func;
					func = getFunction(program, "0x0100194b");
					func.removeParameter(0);
					func.insertParameter(0, my_count, SourceType.USER_DEFINED);
					func = getFunction(program, "0x0100299e");
					func.setVarArgs(true);
					func = getFunction(program, "0x01004132");
					func.removeParameter(0);
					func.insertParameter(0, my_count, SourceType.USER_DEFINED);
					func = getFunction(program, "0x01004a15");
					func.setVarArgs(true);
				}
				catch (DuplicateNameException e) {
					e.printStackTrace();
					Assert.fail(e.getMessage());
				}
				catch (InvalidInputException e) {
					e.printStackTrace();
					Assert.fail(e.getMessage());
				}
			}
Test the merge of the versioned program's listing.
Ghidra/Features/Base/src/test.slow/java/ghidra/app/merge/listing/FunctionMergeManagerTest.java