Reactnative api.get(...).then(...).catch(...).finally 不是函数

我正在进行一个React原生API调用.

从理论上讲，它应该有效-

    import API from "../../utils/API";

  componentDidMount() {
    let merchantId = this.props.merchant.id;
    let api = new API(this.props.gatheredTokens);
    let self = this;
    api.setRetry(10);
    api
      .get("merchantMessages", { repl_str: merchantId })
      .then(response => this.merchantMessageConfiguration(response.data))
      .catch(function (error) {
        console.log(error);
      })
      .finally(function () {
        self.state.list.push(
          <Card
            merchant={self.props.merchant}
            key={self.props.merchant.id}
            bubblemsg={self.state.bubblemsg}
          />
        );
      })
      .finally(function () {
        self.merchantNoticeLoading(self);
      });
  }

然而，我得到了以下错误:

是什么导致了这个错误？代码看起来有效.

下面是get的要点:

 get(API, params = this.defaultParams) {
    this.call = "GET";
    let constructedURL = this.constructURL(API, params);
    axiosRetry(axios, { retries: this.retry });
    return axios.get(constructedURL, this.config);
  }