function createLinkTypeChecker(linkType) {
  var shapes = {
    value: typeof linkType === 'undefined' ?
      React.PropTypes.any.isRequired :
      linkType.isRequired,
    requestChange: React.PropTypes.func.isRequired
  };
  return React.PropTypes.shape(shapes);
}
Creates a PropType that enforces the ReactLink API and optionally checks the
type of the value being passed inside the link. Example:

MyComponent.propTypes = {
  tabIndexLink: ReactLink.PropTypes.link(React.PropTypes.number)
}