-r optional.txt

isort>=4.2.3
pycodestyle==2.5.0
pydocstyle==3.0.0
pytest==4.6.3
pytest-cov==2.7.1
pytest-xdist==1.29.0
Sphinx==2.1.2 ;python_version > '3.0'
Sphinx==1.8.5 ;python_version < '3.0'
