The noxfile.py in the samples template now includes a blacken session. It's great to run this, but I notice that the changes it makes get reverted the next time that synthtool runs. I think it makes sense for blacken to blacken the noxfile, but if used then it shouldn't get reverted.

Since I'm not sure if all of our samples are using black, I propose we add an optional parameter to py_samples that runs blacken when done copying everything.

Reference:

• "unblacken" PR: chore: unblacken snippets noxfile python-bigquery-reservation#66

• synthtool/synthtool/languages/python.py

  Line 96 in 996775e

  def py_samples(*, root: PathOrStr = None, skip_readmes: bool = False) -> None: