How to get label name onclick from a React google 3D pie chart?

Question

I am trying to get clicked section label name of the 3D Pie Chart Google

  <Chart
  chartType="PieChart"
  data={this.state.agentsummary}
  options={options}
  width={"100%"}
  height={"600px"}
  chartEvents={chartEvents}
  />

// but I got null value from row selection

const chartEvents = [
      {
        eventName: "select",
        callback({ chartWrapper }) {
          console.log("Selected ", chartWrapper.getChart().getSelection()[0]);
        },
      },
    ];