* optimization for pangram string * fixup! Format Python code with psf/black push * Update strings/check_pangram.py Co-authored-by: Christian Clauss <cclauss@me.com> * updating DIRECTORY.md * Update strings/check_pangram.py Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com> Co-authored-by: Christian Clauss <cclauss@me.com>