为什么按例子测试出错： “ NoMethodError: undefined method `[]' for #<Set: {#<MIME::Type: application/json>}>”

  params = {
    "redirect": {
      "path": "/12345",
      "target": "/blogs"
    }
  }
  code, body, header = YhsdApi::PrivateApp.put("redirects", params)

出错： NoMethodError: undefined method `[]' for #<Set: {#<MIME::Type: application/json>}>
