Convert bytes to a string in Python ?

I'm using this code to get standard output from an external program:

>>> from subprocess import *

>>> command_stdout = Popen(['ls', '-l'], stdout=PIPE).communicate()[0]

The communicate() method returns an array of bytes:

>>> command_stdout

b'total 0\n-rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file1\n-rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file2\n'

However, I want to work with the output as a normal Python string. So that I could print it like this:

>>> print(command_stdout)

-rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file1

-rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file2

I thought that's what the binascii.b2a_qp() method is for, but when I tried it, I got the same byte array again:

>>> binascii.b2a_qp(command_stdout)

b'total 0\n-rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file1\n-rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file2\n'

How do I convert the bytes value back to string? I mean, using the "batteries" instead of doing it manually. And I'd like it to be OK with Python 3.