anchor.diff:      inherit (self) python libxml2;
     });
   
  -  librepo = pipe pkgs.librepo [
  +  librepo = lib.pipe pkgs.librepo [
       toPythonModule
       (p: p.overrideAttrs (super: { meta = super.meta // { outputsToInstall = [ "py" ]; }; }))
       (p: p.override { inherit python; })
  
positive.code:       }
        else ff;
  
    buildPythonPackage = makeOverridablePythonPackage ( makeOverridable (callPackage ../development/interpreters/python/mk-python-derivation.nix {
      inherit namePrefix;     # We want Python libraries to be named like e.g. "python3.6-${name}"
      inherit toPythonModule; # Libraries provide modules
    }));
  
    buildPythonApplication = makeOverridablePythonPackage ( makeOverridable (callPackage ../development/interpreters/python/mk-python-derivation.nix {
      namePrefix = "";        # Python applications should not have any prefix
      toPythonModule = x: x;  # Application does not provide modules.
    }));
  
negative.code: 
    libsavitar = callPackage ../development/python-modules/libsavitar { };
  
    libselinux = lib.pipe pkgs.libselinux [
      toPythonModule
      (p:
        p.overrideAttrs (super: {
  