Update mk-python-derivation.nix

Author: h0nIg

pkgs/development/interpreters/python/mk-python-derivation.nix

@@ -425,19 +425,8 @@ let
           # default to python's platforms
           platforms = python.meta.platforms;
           isBuildPythonPackage = python.meta.platforms;
-        }
-        //
-          lib.optionalAttrs
-            (
-              attrs ? src
-              && attrs.src ? meta
-              && attrs.src.meta ? identifiers
-              && attrs.src.meta.identifiers ? purlParts
-            )
-            {
-              identifiers.purlParts = attrs.src.meta.identifiers.purlParts;
-            }
-        // meta;
+          identifiers.purlParts = attrs.src.meta.identifiers.purlParts or {};
+        } // meta;
     }
     // optionalAttrs (attrs ? checkPhase) {
       # If given use the specified checkPhase, otherwise use the setup hook.