anchor.diff:  
     pythonPackages = modules // {
   
  -  inherit python isPy26 isPy27 isPy33 isPy34 isPyPy isPy3k pythonName buildPythonPackage;
  +  inherit python isPy26 isPy27 isPy33 isPy34 isPy35 isPyPy isPy3k pythonName buildPythonPackage;
   
     # helpers
   
  
positive.code:   isPy27 = python.majorVersion == "2.7";
    isPy33 = python.majorVersion == "3.3";
    isPy34 = python.majorVersion == "3.4";
    isPyPy = python.executable == "pypy";
    isPy3k = strings.substring 0 1 python.majorVersion == "3";
  
  
negative.code:     if isPy27 then "python27" else
      if isPy33 then "python33" else
      if isPy34 then "python34" else
      if isPy35 then "python35" else
      if isPyPy then "pypy" else "";
  
    modules = python.modules or {
  