mixinNode(node) {
    node = this.visit(node.first);
    switch (node.nodeName) {
      case 'object':
        this.mixinObject(node);
        return nodes.null;
      case 'block':
      case 'atblock':
        this.mixin(node.nodes, this.currentBlock);
        return nodes.null;
    }
  }
Mixin the given `node` to the current block.

@param {Node} node
@api private