docs: private static MethodType widenOperators(MethodType mt) {
          if (mt.parameterCount()==2) {
              Class leftType = mt.parameterType(0);
              Class rightType = mt.parameterType(1);
              
              if (isIntCategory(leftType) && isIntCategory(rightType)) return IIV;
              if (isLongCategory(leftType) && isLongCategory(rightType)) return LLV;
              if (isBigDecCategory(leftType) && isBigDecCategory(rightType)) return GGV;
              if (isDoubleCategory(leftType) && isDoubleCategory(rightType)) return DDV;
              
              return OOV;
          } else if (mt.parameterCount()==1) {
              Class leftType = mt.parameterType(0);
              if (isIntCategory(leftType)) return IV;
              if (isLongCategory(leftType)) return LV;
              if (isBigDecCategory(leftType)) return GV;
              if (isDoubleCategory(leftType)) return DV;
          }
          return mt;
      }