Generates structure file with protons from a list of structure files.

def output_reduce_list(path_list, force=False):
    """Generates structure file with protons from a list of structure files."""
    output_paths = []
    for path in path_list:
        output_path = output_reduce(path, force=force)
        if output_path:
            output_paths.append(output_path)
    return output_paths