``` import React from 'react'; import PropTypes from 'prop-types'; function Hobby(props){ return <li>{props.hobby}</li> } Hobby.propTypes={ hobby:PropTypes.string.isRequired } export default Hobby; ``` ``` import React from 'react'; import PropTypes from 'prop-types'; class Hobby extends React.Component{ render(){ return <li>{this.props.hobby}</li> } } Hobby.propTypes={ hobby:PropTypes.string.isRequired } export default Hobby; ```