[Python] filename with timestamp for auto versioning on HTML cache.

current_date.py

def current_date(format='%Y-%m-%d %H:%M:%S'):
    import datetime
    return datetime.date.today().strftime(format)

get_versioned_filename.py

def get_versioned_filename(base_dir, filename):
    # ref:http://stackoverflow.com/questions/82831/how-do-i-check-if-a-file-exists-using-python 
    import os
    try:
        filepath = os.path.join(base_dir, filename)
        mtime = os.stat(filepath).st_mtime
    except OSError:
        return None
    else:
        return "%s?%s" % (filename, mtime)

kansuuji.py

def kansuuji(number):
    number_map = {
        '1': u'一',
        '2': u'二',
        '3': u'三',
        '4': u'四',
        '5': u'五',
        '6': u'六',
        '7': u'七',
        '8': u'八',
        '9': u'九',
        '0': u'〇',
    }
    number_string = str(number)
    retval = u''
    for c in number_string:
        retval += number_map.get(c, u'')
    return retval