1render() {
2    return (
3      <div>
4        <h5>
5          <NavLink
6            to="/child-a"
7            activeStyle={{ color:'red' }}
8            exact
9          >child-a</NavLink>
10        </h5>
11        <h5>
12          <NavLink
13            to="/child-b"
14            activeStyle={{ color:'red' }}
15            exact
16          >child-b</NavLink>
17        </h5>
18        <div>
19          <div><h2>Hello</h2></div>
20          {this.props.children}
21        </div>
22      </div>
23    );
24  }
25