anchor.diff: -{ lib, buildPythonPackage, fetchPypi
  -, setuptools-scm
  +{ lib
  +, buildPythonPackage
  +, fetchPypi
   , sphinx
   , hypothesis
   , py
  
positive.code: , pytest-benchmark
  , sortedcollections
  , sortedcontainers
  , isPy3k
  }:
  
  buildPythonPackage rec {
    pname = "bidict";
    version = "0.21.2";
    disabled = !isPy3k;
  
    src = fetchPypi {
      inherit pname version;
      sha256 = "4fa46f7ff96dc244abfc437383d987404ae861df797e2fd5b190e233c302be09";
    };
  
    nativeBuildInputs = [ setuptools-scm ];
    propagatedBuildInputs = [ sphinx ];
  
    checkInputs = [
      hypothesis
  
negative.code:     sortedcontainers
    ];
  
    pythonImportsCheck = [ "bidict" ];
  
    meta = with lib; {
      homepage = "https://github.com/jab/bidict";
      description = "Efficient, Pythonic bidirectional map data structures and related functionality";
  