anchor.diff:  , peewee
   , pony
   , pytestCheckHook
  +, python-dateutil
   , zxcvbn
   }:
   
  
positive.code: # extras: common
  , bcrypt
  , bleach
  , flask_mail
  
  # extras: fsqla
  , flask-sqlalchemy
  
negative.code:     peewee
      pony
      pytestCheckHook
      python-dateutil
      zxcvbn
    ]
    ++ passthru.optional-dependencies.babel
  