;(function(window) {
  const str = `
interface FrameRequestCallback {
    (time: number): void;
}
declare function cancelAnimationFrame(handle: number): void;
declare function requestAnimationFrame(callback: FrameRequestCallback): number;  
`
  window.API = window.API || {}
  const API = window.API
  if (API.LibWaEs6) {
    API.LibWaEs6 += str
  } else {
    API.LibWaEs6 = str
  }
})(window)
