anchor.diff:  
     pypy38_prebuilt = callPackage ./pypy/prebuilt.nix {
       # Not included at top-level
  -    self = pkgs.pythonInterpreters.pypy38_prebuilt;
  +    self = __splicedPackages.pythonInterpreters.pypy38_prebuilt;
       sourceVersion = {
         major = "7";
         minor = "3";
  
positive.code: 
    # Minimal versions of Python (built without optional dependencies)
    python3Minimal = (callPackage ./cpython ({
      self = pkgs.python3Minimal;
      inherit passthruFun;
      pythonAttr = "python3Minimal";
      # strip down that python version as much as possible
  
negative.code: in {
  
    python27 = callPackage ./cpython/2.7 {
      self = __splicedPackages.python27;
      sourceVersion = {
        major = "2";
        minor = "7";
  