old_contents: import React from 'react';
  import Title from './Header/Title';
  
  const Header = props => (
    <div>
      <Title title={props.title} />
    </div>
  );
  
  Header.propTypes = {
    title: React.PropTypes.string,
  };
  
  export default Header;
  
new_contents: import React from 'react';
  import Title from './Header/Title';
  
  const Header = props => (
    <div>
      <Title {...props} />
    </div>
  );
  
  export default Header;
  
subject: Use spread attribute