* Pyupgrade to Python 3.9 * updating DIRECTORY.md Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
* pyupgrade --py37-plus **/*.py * fixup! Format Python code with psf/black push
* Implementation of Hardy Ramanujan Algorithm * added docstrings * added doctests * Run Python black on the code * Travis CI: Upgrade to Python 3.8 * Revert to Python 3.7