diff --git a/pkgs/development/python-modules/mcdreforged/default.nix b/pkgs/development/python-modules/mcdreforged/default.nix
index 30991c13c275..daa168105f7b 100644
--- a/pkgs/development/python-modules/mcdreforged/default.nix
+++ b/pkgs/development/python-modules/mcdreforged/default.nix
@@ -52,6 +52,8 @@ buildPythonPackage rec {
     versionCheckHook
   ];
 
+  pythonRelaxDeps = [ "ruamel.yaml" ];
+
   passthru.updateScript = nix-update-script { };
 
   meta = {