docs: private Round resolveRound(FunctionRef fun) {
          if (fun.getOperand().isEmpty() || fun.getOperand().size() > 2) {
              throw new IllegalArgumentException("Could not resolve call to system operator Round.  Expected 1 or 2 arguments.");
          }
          final Round round = of.createRound().withOperand(fun.getOperand().get(0));
          if (fun.getOperand().size() == 2) {
              round.setPrecision(fun.getOperand().get(1));
          }
          builder.resolveCall("System", "Round", new RoundInvocation(round));
          return round;
      }