anchor.diff:  , lib
   , python
   }:
  -
  -with lib;
   
   self:
   
  
positive.code:     inherit (self) python libxml2;
    });
  
    librepo = pipe pkgs.librepo [
      toPythonModule
      (p: p.overrideAttrs (super: { meta = super.meta // { outputsToInstall = [ "py" ]; }; }))
      (p: p.override { inherit python; })
  
negative.code:       }
        else ff;
  
    buildPythonPackage = makeOverridablePythonPackage (lib.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 (lib.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.
    }));
  