human
Here's a good function header given the following:
I wrote the below code

    if (not filePath):
        return None
    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 io.open(filePath, u'rb') as f:
        a = gen(f)
        hashes = [md4_hash(data).digest() for data in a]
        if (len(hashes) == 1):
            return hashes[0].encode(u'hex')
        else:
            return md4_hash(reduce((lambda a, d: (a + d)), hashes, u'')).hexdigest()

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

def get_file_hash(filePath):