createBlockNode_(workspace) {
    const block = workspace.getBlockById(this.blockId);
    return Blockly.ASTNode.createBlockNode(block);
  }
Create an ASTNode pointing to a block.
@param {!Blockly.Workspace} workspace The workspace the user is on.
@returns {Blockly.ASTNode} An AST Node that points to a block.
@public