Filenames with spaces create error about django-s3direct HOT 3 CLOSED

import functools

def safe_key(prefix, file_name):  
    file_name = file_name.replace(' ', '_')
    # Plus any additional file name customization you want.
    key = '/'.join([prefix, file_name])
    return key

S3DIRECT_DESTINATIONS = {
    'a_destination': [
        functools.partial(safe_key, 'someprefix'),
        lambda u: u.is_authenticated(),
        ['image/jpeg', 'image/png'],
        'public-read',
        'somebucket',
    ],
    'another_destination': [
        functools.partial(safe_key, 'anotherprefix'),
        lambda u: u.is_authenticated(),
        ['image/jpeg', 'image/png'],
        'public-read',
        'somebucket',
    ],
}