docs: function (guestInstanceId, contents) {
    const guest = getGuest(guestInstanceId)
    if (!guest) {
      throw new Error(`Invalid guestInstanceId: ${guestInstanceId}`)
    }
    if (guest.hostWebContents !== contents) {
      throw new Error(`Access denied to guestInstanceId: ${guestInstanceId}`)
    }
    return guest
  }