setup.py

from setuptools import setup

extras_require = {}
extras_require["lint"] = sorted({"flake8", "black"})
# c.f. https://networkx.org/documentation/stable/install.html#optional-packages
extras_require["viz"] = sorted({"pydot~=1.4", "dot2tex~=2.11"})
extras_require["test"] = sorted(
    set(
        extras_require["viz"]
        + [
            "pytest~=6.0",
            "pytest-cov>=2.5.1",
            "scikit-hep-testdata>=0.3.1",
            "pydocstyle",
        ]
    )
)
extras_require["develop"] = sorted(
    set(
        extras_require["lint"]
        + extras_require["test"]
        + ["pre-commit", "check-manifest", "bump2version~=1.0", "twine"]
    )
)
extras_require["complete"] = sorted(set(sum(extras_require.values(), [])))

setup(
    extras_require=extras_require,
    use_scm_version=lambda: {"local_scheme": lambda version: ""},
)