message: added all the proptypes
diff: import React from "react";
  +import PropTypes from "prop-types";
  export default class Checkbox extends React.Component {
  + static propTypes = {
  + id: PropTypes.string.isRequired,
  + name: PropTypes.string,
  + label: PropTypes.string,
  + checked: PropTypes.bool,
  + handleChange: PropTypes.func.isRequired
  + };
  render() {
  return (
  <div>
  - <input key="checkbox" type="checkbox" id={this.props.id} name={this.props.name} />
  + <input
  + key="checkbox"
  + type="checkbox"
  + id={this.props.id}
  + name={this.props.name}
  + checked={(this.props.checked || (this.props.hasOwnProperty("checked") && this.props.checked !== false))}
  + onChange={this.props.handleChange}
  + />
  <label key="label" htmlFor={this.props.id}>{this.props.label}</label>
  </div>
  );
  