{ stdenv, fetchPypi, buildPythonPackage, typing, pythonOlder }: buildPythonPackage rec { pname = "mypy_extensions"; version = "0.4.1"; # Tests not included in pip package. doCheck = false; src = fetchPypi { inherit pname version; sha256 = "04h8brrbbx151dfa2cvvlnxgmb5wa00mhd2z7nd20s8kyibfkq1p"; }; propagatedBuildInputs = if pythonOlder "3.5" then [ typing ] else [ ]; meta = with stdenv.lib; { description = "Experimental type system extensions for programs checked with the mypy typechecker"; homepage = "http://www.mypy-lang.org"; license = licenses.mit; maintainers = with maintainers; [ martingms lnl7 ]; }; }