### Question:
MeterIdConverter implements AttributeConverter<MeterId, Long> { @Override public Long toGraphProperty(MeterId value) { if (value == null) { return null; } return value.getValue(); }  @Override Long toGraphProperty(MeterId value); @Override MeterId toEntityAttribute(Long value); static final MeterIdConverter INSTANCE; }### Answer:
@Test public void shouldConvertIdToString() { MeterId meterId = new MeterId(0x123); Long graphObject = MeterIdConverter.INSTANCE.toGraphProperty(meterId); assertEquals(meterId.getValue(), (long) graphObject); }