public static Builder builder() {
    return new Builder();
  }
@Test
  public void testCanUseNullAsPropertyValue() throws JsonProcessingException {
    String jsonNullValueInDefaults =
        "{\"defaults\":{\"warehouse\":null},\"overrides\":{\"clients\":\"5\"}}";
    assertRoundTripSerializesEquallyFrom(
        jsonNullValueInDefaults,
        ConfigResponse.builder()
            .withDefaults(DEFAULTS_WITH_NULL_VALUE)
            .withOverrides(OVERRIDES)
            .build());
    assertRoundTripSerializesEquallyFrom(
        jsonNullValueInDefaults,
        ConfigResponse.builder().withDefault("warehouse", null).withOverrides(OVERRIDES).build());

    String jsonNullValueInOverrides =
        "{\"defaults\":{\"warehouse\":\"s3://bucket/warehouse\"},\"overrides\":{\"clients\":null}}";
    assertRoundTripSerializesEquallyFrom(
        jsonNullValueInOverrides,
        ConfigResponse.builder()
            .withDefaults(DEFAULTS)
            .withOverrides(OVERRIDES_WITH_NULL_VALUE)
            .build());
    assertRoundTripSerializesEquallyFrom(
        jsonNullValueInOverrides,
        ConfigResponse.builder().withDefaults(DEFAULTS).withOverride("clients", null).build());
  }