docs: protected final CALC operator(Class<? extends Operator> operator, Object value) {
          Num tmp = null;
          if (value instanceof Num)
              tmp = (Num)value;
          else
              tmp = new Num(value);
          
          infix.add(CacheExtension.getOperator(operator));
          infix.add(tmp);
          return getThis();
      }