anchor.diff:  
     postPatch = ''
       substituteInPlace pytest.ini \
  +      --replace "filterwarnings = error" "" \
         --replace "--cov=aiosignal" ""
     '';
   
  
positive.code: 
  buildPythonPackage rec {
    pname = "aiosignal";
    version = "1.2.0"; # re-enable tests after 1.2.0
    disabled = pythonOlder "3.6";
  
    src = fetchFromGitHub {
  
negative.code:     frozenlist
    ];
  
    checkInputs = [
      pytest-asyncio
      pytestCheckHook
  