Method "new_folder" results in 400 error response.

[brucejiverson]

This code will fix it

def new_folder(self, folder_name, path=None, location='local'):
"""Create a new folder on OctoPrint's file system
Note: Folder creation is only supported on the local file system.
"""
files = {
'foldername': (None, folder_name),
}
if path:
files['path'] = (None, path)

return self._post('/api/files/{}'.format(location), files=files)