b2sum

def b2sum(fname):
    buffsize = 1024 * 512
    buffer = bytearray(buffsize)
    view = memoryview(buffer)
    blake = hashlib.blake2b()
    with open(fname, 'rb') as fd:
        while True:
            n = fd.readinto(buffer)
            if n == buffsize:
                blake.update(buffer)
            elif n == 0:
                break
            else:
                blake.update(view[:n])
    return blake.hexdigest()