diff --git a/plugins/XmlMaterialProfile/XmlMaterialProfile.py b/plugins/XmlMaterialProfile/XmlMaterialProfile.py
index 4cc3638f71..d7d11a1f44 100644
--- a/plugins/XmlMaterialProfile/XmlMaterialProfile.py
+++ b/plugins/XmlMaterialProfile/XmlMaterialProfile.py
@@ -343,7 +343,7 @@ class XmlMaterialProfile(InstanceContainer):
 
         return stream.getvalue().decode("utf-8")
 
-    def getFileName(self):
+    def getFileName(self) -> str:
         return (self.getMetaDataEntry("base_file") + ".xml.fdm_material").replace(" ", "+")
 
     # Recursively resolve loading inherited files