How to use the prosemirror-history.undo function in prosemirror-history

undo(n = 1) {
    for (let i = 0; i < n; i += 1) {
      undo(this.state, tr => this.apply(tr));
    }
    return this;
  }

  enable: state => undo(state),
  icon: icons.undo

	select: state => undo(state),
	icon: ""

            [`${mod}-Z`]: () => undo(view.state, view.dispatch),
            [`Shift-${mod}-Z`]: () => redo(view.state, view.dispatch),

execute = (
    state: EditorState,
    dispatch: ?(tr: Transform) => void,
    view: ?EditorView
  ): boolean => {
    return undo(state, dispatch);
  };
}

          "Mod-z": () => undo(this.outerView.state, this.outerView.dispatch),
          "Mod-y": () => redo(this.outerView.state, this.outerView.dispatch)

  "Mod-z": (state, dispatch) => undo(state, dispatch)
});

      [`${mod}-Z`]: () => undo(view.state, view.dispatch),
      [`Shift-${mod}-Z`]: () => redo(view.state, view.dispatch),

undo = () => {
    const { pmstate } = this.props;
    const { state, dispatch } = pmstate.pmview;
    undo(state, dispatch);
  };

doUndo(e: CustomEvent) {
    e.stopPropagation()
    e.preventDefault()
    if (this.editorView) {
      undo(this.editorView.state, this.editorView.dispatch)
      this.editorView.focus()
    }
  }