安装react包后，无法使用状态进行操作

import React from 'react';

class MyComponent extends React.Component {
  // 组件的代码
}

class MyComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      // 初始化状态
    };
  }
  // 组件的其他代码
}

class MyComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      count: 0
    };
  }
  
  handleClick() {
    this.setState({ count: this.state.count + 1 });
  }
  
  render() {
    return (
      <div>
        <p>Count: {this.state.count}</p>
        <button onClick={() => this.handleClick()}>Increment</button>
      </div>
    );
  }
}