react純組件的propsType和defaultProps怎么寫

react是15.3

import React, { Component, PropTypes} from 'react'


const FormTableLayout = (props) =>{

  return (
    <div className="farm-card">
    </div>
  )
}

// 無效
FormTableLayout.PropTypes = {
  title:PropTypes.string,
  returnBtn:PropTypes.bool,
}