anchor.diff:  # extras: mfa
   , cryptography
   , phonenumbers
  -, pyqrcode
   
   # propagates
   , blinker
  
positive.code:     peewee
      pony
      pytestCheckHook
      zxcvbn
    ]
    ++ passthru.optional-dependencies.babel
  
negative.code: # extras: common
  , bcrypt
  , bleach
  , flask-mailman
  , qrcode
  
  # extras: fsqla
  , flask-sqlalchemy
  