anchor.diff: -{ stdenv
  -, lib
  +{ lib
   , buildPythonPackage
   , fetchFromGitHub
   , isPy27
  
positive.code:     pytestCheckHook
    ];
  
    # Don't run tests for Python 2.7 or Darwin
    # Nearly 50% of the test suite requires local network access
    # which isn't allowed on sandboxed Darwin builds
    doCheck = !(isPy27 || stdenv.isDarwin);
    pytestFlagsArray = [ "--ignore python2" ];
    pythonImportsCheck = [ "httplib2" ];
  
    meta = with lib; {
      description = "A comprehensive HTTP client library";
  
negative.code: 
    propagatedBuildInputs = [ pyparsing ];
  
    pythonImportsCheck = [ "httplib2" ];
  
    # Don't run tests for Python 2.7
    doCheck = !isPy27;
  
    checkInputs = [
      mock
      pytest-forked
  