return UrlFetchApp.fetch(
    "https://api.dropboxapi.com/2/files/list_folder",
    {
      "Content-Type" : "application/json",
      "method" : "post",
      "headers" : {
        "Authorization" : "Bearer (TOKEN)",
        "Content-Type" : "application/json"
      },
      "body" : {
        "path" : ""
      },
      "muteHttpExceptions" : false
    }
  );