human
I wrote the below code

    md4 = hashlib.new(u'md4').copy
    def gen(f):
        while True:
            x = f.read(9728000)
            if x:
                (yield x)
            else:
                return
    def md4_hash(data):
        m = md4()
        m.update(data)
        return m
    with open(filename, u'rb') as f:
        a = gen(f)
        hashes = [md4_hash(data).digest() for data in a]
        if (len(hashes) == 1):
            return to_hex(hashes[0])
        else:
            return md4_hash(reduce((lambda a, d: (a + d)), hashes, u'')).hexd

What's a good function header?
assistant
#Here's a good function header.

def hash_filehash(filename):