-r optional.txt

black==20.8b1
flake8==3.9.0
flake8-black==0.2.1
flake8-breakpoint==1.1.0
flake8-isort==4.0.0
flake8-mutable==1.2.0
flake8-no-u-prefixed-strings==0.2
flake8-polyfill==1.0.2
isort==5.8.0
pre-commit==2.11.1
pycodestyle==2.7.0
pydocstyle==6.0.0
pytest==6.2.2
pytest-cov==2.11.1
pytest-xdist==2.2.1
pyupgrade==2.11.0
Sphinx==3.5.3
twine==3.4.1
virtualenv==20.4.3
