How to use the @jupyterlab/codeeditor.CodeEditor.defaultSelectionStyle function in @jupyterlab/codeeditor

modelDB.connected.then(() => {
        if (!cell.isDisposed) {
          // Setup the selection style for collaborators.
          let localCollaborator = modelDB.collaborators.localCollaborator;
          cell.editor.uuid = localCollaborator.sessionId;
          cell.editor.selectionStyle = {
            ...CodeEditor.defaultSelectionStyle,
            color: localCollaborator.color
          };
        }
      });
    }

constructor(options: CodeMirrorEditor.IOptions) {
    let host = (this.host = options.host);
    host.classList.add(EDITOR_CLASS);
    host.classList.add('jp-Editor');
    host.addEventListener('focus', this, true);
    host.addEventListener('blur', this, true);
    host.addEventListener('scroll', this, true);

    this._uuid = options.uuid || UUID.uuid4();

    // Handle selection style.
    let style = options.selectionStyle || {};
    this._selectionStyle = {
      ...CodeEditor.defaultSelectionStyle,
      ...(style as CodeEditor.ISelectionStyle)
    };

    let model = (this._model = options.model);
    let config = options.config || {};
    let fullConfig = (this._config = {
      ...CodeMirrorEditor.defaultConfig,
      ...config
    });
    let editor = (this._editor = Private.createEditor(host, fullConfig));

    let doc = editor.getDoc();

    // Handle initial values for text, mimetype, and selections.
    doc.setValue(model.value.text);
    this.clearHistory();

constructor(options: CodeMirrorEditor.IOptions) {
    let host = this.host = options.host;
    host.classList.add(EDITOR_CLASS);
    host.classList.add('jp-Editor');
    host.addEventListener('focus', this, true);
    host.addEventListener('scroll', this, true);

    this._uuid = options.uuid || uuid();

    // Handle selection style.
    let style = options.selectionStyle || {};
    this._selectionStyle = {
        ...CodeEditor.defaultSelectionStyle,
        ...style as CodeEditor.ISelectionStyle
    };

    let model = this._model = options.model;
    let editor = this._editor = CodeMirror(host, {});
    Private.handleConfig(editor, options.config || {});

    let doc = editor.getDoc();

    // Handle initial values for text, mimetype, and selections.
    doc.setValue(model.value.text);
    this._onMimeTypeChanged();
    this._onCursorActivity();

    // Connect to changes.
    model.value.changed.connect(this._onValueChanged, this);

constructor(options: CodeMirrorEditor.IOptions) {
    let host = (this.host = options.host);
    host.classList.add(EDITOR_CLASS);
    host.classList.add('jp-Editor');
    host.addEventListener('focus', this, true);
    host.addEventListener('blur', this, true);
    host.addEventListener('scroll', this, true);

    this._uuid = options.uuid || UUID.uuid4();

    // Handle selection style.
    let style = options.selectionStyle || {};
    this._selectionStyle = {
      ...CodeEditor.defaultSelectionStyle,
      ...(style as CodeEditor.ISelectionStyle)
    };

    let model = (this._model = options.model);
    let config = options.config || {};
    let fullConfig = (this._config = {
      ...CodeMirrorEditor.defaultConfig,
      ...config
    });
    let editor = (this._editor = Private.createEditor(host, fullConfig));

    let doc = editor.getDoc();

    // Handle initial values for text, mimetype, and selections.
    doc.setValue(model.value.text);
    this.clearHistory();

void modelDB.connected.then(() => {
        let collaborators = modelDB.collaborators;
        if (!collaborators) {
          return;
        }

        // Setup the selection style for collaborators
        let localCollaborator = collaborators.localCollaborator;
        this.editor.uuid = localCollaborator.sessionId;

        this.editor.selectionStyle = {
          ...CodeEditor.defaultSelectionStyle,
          color: localCollaborator.color
        };

        collaborators.changed.connect(this._onCollaboratorsChanged, this);
        // Trigger an initial onCollaboratorsChanged event.
        this._onCollaboratorsChanged();
      });
    }

modelDB.connected.then(() => {
        if (!cell.isDisposed) {
          // Setup the selection style for collaborators.
          let localCollaborator = modelDB.collaborators.localCollaborator;
          cell.editor.uuid = localCollaborator.sessionId;
          cell.editor.selectionStyle = {
            ...CodeEditor.defaultSelectionStyle,
            color: localCollaborator.color
          };
        }
      });
    }

it('should be the selection style of the editor', () => {
      expect(editor.selectionStyle).to.deep.equal(
        CodeEditor.defaultSelectionStyle
      );
    });