anchor.diff:  
   buildPythonPackage rec {
     pname = "limits";
  -  version = "2.6.2";
  +  version = "2.6.3";
     format = "setuptools";
   
     disabled = pythonOlder "3.7";
  
positive.code:     postFetch = ''
        rm "$out/limits/_version.py"
      '';
      hash = "sha256-1TfwGxEgf6LFYSaNLyVRtJVOnTVNxvswoKMFNWrNOv0=";
    };
  
    propagatedBuildInputs = [
  
negative.code:     substituteInPlace pytest.ini \
        --replace "--cov=limits" "" \
        --replace "-K" ""
  
      # Recreate _version.py, deleted at fetch time due to non-reproducibility.
      echo 'def get_versions(): return {"version": "${version}"}' > limits/_version.py
  