docs: public static SameDiff create(SameDiff originalSameDiff) {
          SameDiff ret = SameDiff.builder()
                  .sameDiffFunctionInstances(originalSameDiff.sameDiffFunctionInstances)
                  .build();
          ret.variables.putAll(originalSameDiff.variables);
          //ensuring proper sameDiff reference
          DifferentialFunctionFactory differentialFunctionFactory = new DifferentialFunctionFactory(ret);
          ret.functionFactory = differentialFunctionFactory;
          return ret;
      }