check manual yaml file and re-format it to formulized one

yml_format.py

#!/usr/bin/python

import sys
import yaml

def main():
    """check.py: a simple tool to check yaml format
    Usage: check.py <yaml_filename>
    """
    mode = 'piped'
    if len(sys.argv) == 3:
        mode = 'file'
        of_name = sys.argv[2]
    if_name = sys.argv[1]
    with open(if_name, 'r') as if_stream:
        res = yaml.dump(yaml.load(if_stream), default_flow_style=False, allow_unicode=True)
        if mode == 'file':
            with open(of_name, 'wb') as of_stream:
                of_stream.write(res)
        else:
            print res

main()