【python】计算文件md5值

import md5
import sys

def sumfile(fobj):   
    m = md5.new()
    while True:
        d = fobj.read(8096)
        if not d:
            break
        m.update(d)
    return m.hexdigest()


def md5sum(fname):   
    if fname == '-':
        ret = sumfile(sys.stdin)
    else:
        try:
            f = file(fname, 'rb')
        except:
            return 'Failed to open file'
        ret = sumfile(f)
        f.close()
    return ret


if __name__ == '__main__':
    for fname in sys.argv[1:]:
        print '%32s  %s' % (md5sum(fname), fname)