anchor.diff:  , buildPythonPackage
   , fetchPyPi
   , isPy3k
  +, lib
   
   , constantly
   , incremental
  
positive.code:   # Tests are not fully compatible with Python 3
    doCheck = !isPy3k;
  
    meta = with stdenv.lib; {
      description = "An event-driven networking engine written in Python";
      homepage = https://twistedmatrix.com/;
      license = licenses.mit;
  
negative.code:     package = "Twisted";
      inherit version;
      type = ".tar.bz2";
      sha256 = "d0fe115ea7ef8cf632d05103de60356c6e992b2153d6830bdc4476f8accb1fca";
    };
  
    propagatedBuildInputs = [
  