diff --git a/pkgs/development/python-modules/azure-mgmt-datamigration/default.nix b/pkgs/development/python-modules/azure-mgmt-datamigration/default.nix
index dc889deba12a..93c294e4be95 100644
--- a/pkgs/development/python-modules/azure-mgmt-datamigration/default.nix
+++ b/pkgs/development/python-modules/azure-mgmt-datamigration/default.nix
@@ -27,9 +27,10 @@ buildPythonPackage rec {
     azure-mgmt-nspkg
   ];
 
+  # still needed when overriding to previous versions
+  # E.g. azure-cli
   postInstall = lib.optionalString isPy3k ''
-    rm $out/${python.sitePackages}/azure/__init__.py
-    rm $out/${python.sitePackages}/azure/mgmt/__init__.py
+    rm -f $out/${python.sitePackages}/azure/{,mgmt/}__init__.py
   '';
 
   # has no tests