public static OutputInstruction createOutput(final PortNumber number) {
        checkNotNull(number, "PortNumber cannot be null");
        return new OutputInstruction(number);
    }
@Test
    public void testCreateOutputMethod() {
        final Instruction instruction = Instructions.createOutput(port2);
        final Instructions.OutputInstruction outputInstruction =
                checkAndConvert(instruction,
                        Instruction.Type.OUTPUT,
                        Instructions.OutputInstruction.class);
        assertThat(outputInstruction.port(), is(equalTo(port2)));
    }