anchor.diff: -{ lib, buildPythonPackage, fetchPypi, isPy27
  +{ lib, buildPythonPackage, fetchPypi, isPy27, fetchpatch
   , alembic
   , click
   , cloudpickle
  
positive.code:     sqlalchemy
      gorilla
      gunicorn
    ];
  
    meta = with lib; {
  
negative.code: , sqlalchemy
  , gorilla
  , gunicorn
  , prometheus-flask-exporter
  , importlib-metadata
  }:
  
  buildPythonPackage rec {
  