'str' object has no attribute 'decode' Python 3

Question

import sys

script, error = sys.argv


def main(language_file, errors):
    line = language_file.readline()

    if line:
        print_line(line, errors)
        return main(language_file, errors)


def print_line(line, errors):
    raw_bytes = line.strip()
    cooked_string = raw_bytes.decode(errors=errors)
    print(raw_bytes, "<===>", cooked_string)


languages = open("languages2.txt")

main(languages, error)

If I run this I get 'str' object has no attribute 'decode'.

The languages2.txt file only contains bytes which I want to decode.

If I try raw_bytes.encode(errors=errors) the program runs but obviously prints out only the bytes 2 times.

I'm new to this, so sorry for the dumb question.

Answer 1

By default, the file object will decode the bytes read (ie text mode). If you want to do the decoding yourself you have to open the file in binary mode.