git checkout the oldest nuttx-apps commit that is no younger than the checked out nuttx commit

nuttx_apps_checkout.py

import subprocess

def extract_commit(log):
    return log[7:7+40]

def extract_date(log):
    return log.splitlines()[4].split("CommitDate:")[1].strip()

outp = subprocess.check_output("git log -1 --pretty=fuller", shell=True).decode()
commit = extract_commit(outp)
date = extract_date(outp)
print(f'This nuttx commit ({commit}) dated "{date}"')

outp = subprocess.check_output(f'git -C ../apps log -1 --pretty=fuller --until="{date}" upstream/master', shell=True).decode()
commit = extract_commit(outp)
date = extract_date(outp)
print(f'will use this apps commit ({commit}) dated "{date}"')

subprocess.check_call(f"git -C ../apps checkout {commit}", shell=True)