我有下面的代码，我可以选择一个文档（pdf文件）使用了mart-document-picker，现在我想上传到cloudinary。然而，我得到了一个错误[SyntaxError: JSON Parse error: Unexpected token: <]。我的假设是我错误地将formData发送到了Cloudinary API，但我不确定我到底做错了什么。我确实去了Cloudinary设置，并确保我启用了pdf和zip文件上传。
下面是我的代码：

import * as React from "react";
import * as DocumentPicker from "expo-document-picker";
const cloudName = "example";
const apiKey = "example";
export default function MyUploadScreen({ navigation }) {
const [pickedFile, setPickedFile] = React.useState(null);
const [uploadedFile, setUploadedFile] = React.useState(null);
  const pickFile = async () => {
    try {
      const filePickResponse = await DocumentPicker.getDocumentAsync({
        type: "*/*",
      });
      if (filePickResponse.type === "success") {
        setPickedFile({
          name: filePickResponse.name,
          type: filePickResponse.mimeType,
          uri: filePickResponse.uri,
        });
      }
    } catch (error) {
      console.log(error);
    }
  };
const uploadFile = async () => {
    //Add your cloud name
    let apiUrl = "https://api.cloudinary.com/v1_1/${cloudName}/document/upload";
    const formData = new FormData();
    formData.append("document", pickedFile);
    formData.append("file", pickedFile);
    formData.append("api_key", apiKey);
    formData.append("upload_preset", "example");
    const options = {
      method: "POST",
      body: formData,
      headers: {
        Accept: "application/json",
        "Content-Type": "multipart/form-data",
      },
    };
    try {
      const fileUploadResponse = await fetch(cloudinaryBaseUrl, {
        body: formData,
        method: "POST",
        headers: {
          Accept: "application/json",
          "Content-Type": "multipart/form-data",
        },
      });
      const jsonResponse = await fileUploadResponse.json();
      console.log(jsonResponse); // This will be the success response with id, secure_url, public_id, asset_id etc..
      setUploadedFile(jsonResponse);
    } catch (error) {
      console.log(error);
    }
};

字符串
文档能够被正确地拾取。这里出了什么问题，导致上传文档时出错？