public static L3ModificationInstruction modArpTha(MacAddress addr) {
        checkNotNull(addr, "Dst l3 ARP address cannot be null");
        return new ModArpEthInstruction(L3SubType.ARP_THA, addr);
    }
@Test
    public void testModArpThaMethod() {
        final Instruction instruction = Instructions.modArpTha(mac1);
        final L3ModificationInstruction.ModArpEthInstruction modArpEthInstruction =
                checkAndConvert(instruction,
                                Instruction.Type.L3MODIFICATION,
                                L3ModificationInstruction.ModArpEthInstruction.class);
        assertThat(modArpEthInstruction.subtype(),
                   is(L3ModificationInstruction.L3SubType.ARP_THA));
        assertThat(modArpEthInstruction.mac(), is(mac1));
    }