Popen does not show part of the data

[Arkantr]

Hi! It's my code

ommand_line = 'git log --oneline'
process = subprocess.Popen(command_line, shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
output = process.communicate()[0].decode("utf-8")
print(output )

I expect to see for example

Output:
6934123 (HEAD -> master, tag: v1.5, origin/master, origin/HEAD) no message
e839345 (tag: v1.4) no message
717c567 e
f7c8543 merge

But I see

Output:
6934123 no message
e839345 no message
717c567 e
f7c8543 merge

Can i get first result?