public static L2ModificationInstruction modMplsLabel(MplsLabel mplsLabel) {
        checkNotNull(mplsLabel, "MPLS label cannot be null");
        return new L2ModificationInstruction.ModMplsLabelInstruction(mplsLabel);
    }
@Test
    public void testModMplsMethod() {
        final MplsLabel mplsLabel = MplsLabel.mplsLabel(33);
        final Instruction instruction = Instructions.modMplsLabel(mplsLabel);
        final L2ModificationInstruction.ModMplsLabelInstruction modMplsLabelInstruction =
                checkAndConvert(instruction,
                        Instruction.Type.L2MODIFICATION,
                        L2ModificationInstruction.ModMplsLabelInstruction.class);
        assertThat(modMplsLabelInstruction.label(), is(equalTo(mplsLabel)));
        assertThat(modMplsLabelInstruction.subtype(),
                is(equalTo(L2ModificationInstruction.L2SubType.MPLS_LABEL)));
    }