def read_chunks(filename, mode="r", chunk_size=32):
    with open(filename, mode) as f:
        while True:
            data = f.read(chunk_size)
            if not data:
                break
            yield data


def main():
    filename = "/Users/bob.smith/files/really_really_big.dat"
    for chunk in read_chunks(filename):
        print(chunk)