How to use Just in multipart?

[goribchat]

I want to uplad the image file on server using swift 4.
Just.post(
"http://justiceleauge.org/member/register",data: ["username": "abc", "password":"test"],files: ["product_image" : .url(URL(fileURLWithPath: editProfile_image_path), nil)]) { r in
if r.ok { } }
but image file is not uploading. please help