def replace(source_files):
    """Utility function to replace empty files list"""
    replace_files = list(source_files)
    for o in replace_files:
        o.name = o.name[:-1] + '0'
        o.index = o.index[0], 0
        o.out_index = None
        o.in_index = None
    replace_data = [(o.name, None) for o in replace_files]
    return replace_files, replace_data
