diff --git a/pkgs/development/python-modules/py-serializable/default.nix b/pkgs/development/python-modules/py-serializable/default.nix
index dd7b8dd4312d..b0e0f0284cb4 100644
--- a/pkgs/development/python-modules/py-serializable/default.nix
+++ b/pkgs/development/python-modules/py-serializable/default.nix
@@ -26,6 +26,8 @@ buildPythonPackage rec {
 
   build-system = [ poetry-core ];
 
+  pythonRelaxDeps = [ "defusedxml" ];
+
   dependencies = [ defusedxml ];
 
   nativeCheckInputs = [