code: @NullSafe
    @Override
    @SuppressWarnings("unchecked")
    public <R extends Registry<Converter<?, ?>>> R unregister(Converter<?, ?> converter) {
  
      for (Iterator<Converter<?, ?>> iterator = iterator(); iterator.hasNext(); ) {
        if (iterator.next().equals(converter)) {
          iterator.remove();
          converter.setConversionService(null);
        }
      }
  
      return (R) this;
    }
docs: Unregisters the {@link Converter} from this {@link ConverterRegistry}.
  
  @param converter {@link Converter} to unregister.
  @return this {@link ConverterRegistry}.
  @see org.cp.elements.data.conversion.Converter
  @see #register(Converter)