code: function() {
      this.jsonInit({
        "message0": Blockly.Msg.COLOUR_RANDOM_TITLE,
        "output": "Colour",
        "colour": Blockly.Blocks.colour.HUE,
        "tooltip": Blockly.Msg.COLOUR_RANDOM_TOOLTIP,
        "helpUrl": Blockly.Msg.COLOUR_RANDOM_HELPURL
      });
    }
docs: Block for random colour.
  @this Blockly.Block