Im trying to use the multiparty library and follow its documentation, using nextjs, I get the error "TypeError: req.on is not a function", why?

Question

 import multiparty from "multiparty";

export const POST = async (req, res) => {
  try {
    const form = new multiparty.Form();
    const { fields, files } = await new Promise((resolve, reject) => {
      form.parse(req, (err, fields, files) => {
        if (err) reject(err);
        resolve({ fields, files });
      });
    });
    console.log("length", files.length);
    console.log(fields);
    return new Response("Ok", { status: 200 });
  } catch (error) {
    console.log(error);
    return new Response("Not Ok", { status: 200 });
  }
};

Error:TypeError: req.on is not a function

I was expecting an "Ok" after following its documentation, below is the calling of my api and I don't think the problem lies here but maybe just in case.

 const uploadPhoto = async (ev) => {
    const files = ev.target?.files;
    if (files.length > 0) {
      const data = new FormData();
      for (const file of files) {
        data.append("file", file);
      }
      const response = await axios.post("/api/upload", data);
      console.log(response.data);
    }