code: function _createEditorForDocument(doc, makeMasterEditor, container, range, editorOptions) {
          var editor = new Editor(doc, makeMasterEditor, container, range, editorOptions);
  
          editor.on("focus", function () {
              _notifyActiveEditorChanged(editor);
          });
  
          editor.on("beforeDestroy", function () {
              if (editor.$el.is(":visible")) {
                  _saveEditorViewState(editor);
              }
          });
  
          return editor;
      }
docs: Creates a new Editor bound to the given Document.
  The editor is appended to the given container as a visible child.
  @private
  @param {!Document} doc  Document for the Editor's content
  @param {!boolean} makeMasterEditor  If true, the Editor will set itself as the private "master"
  Editor for the Document. If false, the Editor will attach to the Document as a "slave."
  @param {!jQueryObject} container  Container to add the editor to.
  @param {{startLine: number, endLine: number}=} range If specified, range of lines within the document
  to display in this editor. Inclusive.
  @param {!Object} editorOptions If specified, contains editor options that can be passed to CodeMirror
  @return {Editor} the newly created editor.