def METHOD_NAME(fs_storage):
    class CustomStorage(FileSystemStorage):
        def get_local_path(self, file_id):
            return Storage.get_local_path(self, file_id)
    storage = CustomStorage(fs_storage.path)
    f, __ = storage.save('test.txt', 'unused/unused', 'unused', b'hello world')
    with storage.get_local_path(f) as path:
        with open(path, 'rb') as fd:
            assert fd.read() == b'hello world'
    assert not os.path.exists(path)