I’m writing 2 classes, one saves, one loads. 
The separation is due to the processes being independent (saving / loading of machine learning models.)
To make sure there isn’t any overwrite, I use Path.makedir that fails on existent directories, and always creates a timestamped directory (as said, if it’s not already there.)
The format I like for timestamp looks like this: 2024_12_08_T15_17_16Z. It’s reasonably unique in my circumstances, and also readable.
Now, when loading a model, the user can pass the parent folder and optionally the timestamped one (for obvious reasons, it’s hard to type.)
I haven’t found any similar format that can directly be parsed by datetime and return a boolean “date or not date”. Even the datetime.fromisoformat(...) only accepts date, not time.
I currently use a regex:
def is_date_format(dirname: Path) -> bool:
"""Make sure the directory is the format we chose for saving."""
regex = r"\d{4}_(:?\d{2}_){2}T(:?\d{2}_){2}\d{2}Z$"
return bool(re.match(regex, dirname.name))
that I use both in saving and loading, ensuring that at some point the saving format was not changed.
So, if at some point the saving format changes to 12_08_T15_17_16Z the regex will fail.
Does this approach look reliable to you, or you’d recommend something else?