[galaxy-dev] create a folder inside a library folder using API

Hi, How can I create a folder inside another library folder? I tried:

lib_create_data = { 'name':'mm9', 'create_type': 'folder', } submit(api_key, api_url + "libraries/%s/contents" % library_id, lib_create_data, return_formatted=False)

Where library_id is the upper library folder id.

But this failed with the following error: Error. "Missing requred 'folder_id' parameter."

Does someone know how to do this? Thanks, Hagai