code: function MathOperation() {
          this.addInput("A", "number");
          this.addInput("B", "number");
          this.addOutput("=", "number");
          this.addProperty("A", 1);
          this.addProperty("B", 1);
          this.addProperty("OP", "+", "enum", { values: MathOperation.values });
      }
docs: Math operation