text: import React, { Component } from 'react';
  import PropTypes from 'prop-types'
  import './App.css';
  
  class MyTitle extends Component {
      render () {
          return (
              <h1>{this.props.title}</h1>
          )
      }
  }
  MyTitle.propTypes = {
      title: PropTypes.string
  }
  
  class App extends Component {
      render() {
          const data = '123'
          return (
              <div className="App">
                  <MyTitle title={data} />
              </div>
          );
      }
  }
  
  export default App;
  