code: public static String underscoreSeparated(String camelCaseName) {
          return StringUtils.lowerCase(
                  Arrays.stream(StringUtils.split(camelCaseName, SubFacet.SEPARATOR))
                          .flatMap(component -> Arrays.stream(StringUtils.splitByCharacterTypeCamelCase(component)))
                          .collect(Collectors.joining("_")));
      }
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