anchor.diff:  , alabaster
   , docutils
   , imagesize
  +, importlib-metadata
   , jinja2
   , packaging
   , pygments
   , requests
  -, setuptools
   , snowballstemmer
   , sphinxcontrib-applehelp
   , sphinxcontrib-devhelp
  
positive.code:     packaging
      pygments
      requests
      setuptools
      snowballstemmer
      sphinxcontrib-applehelp
      sphinxcontrib-devhelp
  
negative.code:     sphinxcontrib-serializinghtml
      # extra[docs]
      sphinxcontrib-websupport
    ] ++ lib.optionals (pythonOlder "3.10") [
      importlib-metadata
    ];
  
    checkInputs = [
  