gistfile1.py

def touch(filename):
    open(filename, 'a').close()

def fetch():
    r = requests.get(SOURCE)
    s_new = hashlib.sha1(r.content).digest()

    touch('checksum')
    f = open('checksum', 'r+')
    s_old = f.read(20)
    
    f.seek(0)
    f.write(s_new)
    f.close()

    return r.text, s_new != s_old