What is the curl command to upload a list of files from an input form in flask?

I need the curl command to upload a list of files from a form file input field. What I have tried:

curl -b cookies.txt -X POST http://localhost:8081/rt/api/v1.0/add -d '{"title":"Website updated", "description": "Not accessible", "requestor":"[email protected]", "mfiles":["file1.txt","file2.txt"]}' -H 'Content-type:Application/json'

The api to upload the files:

  for f in request.files.getlist('mfiles'):
        filename = secure_filename(f.filename)
        f.save(os.path.join(upload_folder, filename))

This gives me error: Statement is not an insert() expression construct.

What is the exact curl to do so? I am using Flask 0.12, python 2.7