code: function Report(options, ast) {
    this.options = options;
    this.ast = ast;
    this.items = {root: {type: 'group', items: []}};
    this._home = null;
  }
docs: /*
  Creates an empty report to be filled in by running rules against the AST.
  @param {Object} options Doctor options.
  @param {AstNode} ast Extended AST created from parsing source and extending with
  AstNode.