anchor.diff:    lammps-cython = throw "no longer builds and is unmaintained";
     MechanicalSoup = mechanicalsoup; # added 2021-06-01
     pam = python-pam; # added 2020-09-07.
  -  PasteDeploy = pastedeploy;
  -  powerlineMemSegment = powerline-mem-segment;
  +  PasteDeploy = pastedeploy; # added 2021-10-07
  +  powerlineMemSegment = powerline-mem-segment; # added 2021-10-08
     privacyidea = throw "renamed to pkgs.privacyidea"; # added 2021-06-20
     prometheus_client = prometheus-client; # added 2021-06-10
  -  prompt_toolkit = prompt-toolkit;
  +  prompt_toolkit = prompt-toolkit; # added 2021-07-22
     pylibgen = throw "pylibgen is unmaintained upstreamed, and removed from nixpkgs"; # added 2020-06-20
     pymssql = throw "pymssql has been abandoned upstream."; # added 2020-05-04
     pysmart-smartx = pysmart; # added 2021-10-22
  
positive.code:   requests_toolbelt = requests-toolbelt; # added 2017-09-26
    rotate-backups = throw "pythonPackages.rotate-backups was removed in favor of the top-level rotate-backups"; # added 2021-07-01
    scikitlearn = scikit-learn; # added 2021-07-21
    selectors34 = throw "selectors34 has been removed: functionality provided by Python itself; archived by upstream."; # Added 2021-06-10
    setuptools_scm = setuptools-scm; # added 2021-06-03
    smart_open = smart-open; # added 2021-03-14
    smmap2 = throw "smmap2 has been deprecated, use smmap instead."; # added 2020-03-14
    sphinxcontrib_plantuml = sphinxcontrib-plantuml;
    sqlalchemy_migrate = sqlalchemy-migrate; # added 2021-10-28
    topydo = throw "python3Packages.topydo was moved to topydo"; # 2017-09-22
    tvnamer = throw "python3Packages.tvnamer was moved to tvnamer"; # 2021-07-05
    WazeRouteCalculator = wazeroutecalculator; # 2021-09-29
    websocket_client = websocket-client;
    zc-buildout221 = zc-buildout; # added 2021-07-21
  })
  
negative.code:   ### Deprecated aliases - for backward compatibility
  
  mapAliases ({
    blockdiagcontrib-cisco = throw "blockdiagcontrib-cisco is not compatible with blockdiag 2.0.0 and has been removed."; # added 2020-11-29
    bt_proximity = bt-proximity; # added 2021-07-02
    bugseverywhere = throw "bugseverywhere has been removed: Abandoned by upstream."; # added 2019-11-27
    class-registry = phx-class-registry; # added 2021-10-05
    ConfigArgParse = configargparse; # added 2021-03-18
    dateutil = python-dateutil; # added 2021-07-03
    detox = throw "detox is no longer maintained, and was broken since may 2019"; # added 2020-07-04
    dftfit = throw "it's dependency lammps-cython no longer builds"; # added 2021-07-04
    diff_cover = diff-cover; # added 2021-07-02
    discogs_client = discogs-client; # added 2021-07-02
    djangorestframework-jwt = drf-jwt; # added 2021-07-20
    dns = dnspython; # added 2017-12-10
    dogpile_cache = dogpile-cache; # added 2021-10-28
    faulthandler = throw "faulthandler is built into ${python.executable}"; # added 2021-07-12
    gitdb2 = throw "gitdb2 has been deprecated, use gitdb instead."; # added 2020-03-14
    glances = throw "glances has moved to pkgs.glances"; # added 2020-20-28
    google_api_python_client = google-api-python-client; # added 2021-03-19
  