diff --git a/src/openpecha/pecha/__init__.py b/src/openpecha/pecha/__init__.py
index 9975839..25f2f2a 100644
--- a/src/openpecha/pecha/__init__.py
+++ b/src/openpecha/pecha/__init__.py
@@ -42,9 +42,9 @@ def set_layer(
 
         """layer key is a tuple of layer label and layer id"""
         """ A particular volume can have multiple layers with same label but different id"""
-        layer_id = get_uuid()[:4]
-        self.layers[base_name][(annotation_type, layer_id)] = layer
-        return layer_id
+        layer_subtype_id = get_uuid()[:4]
+        self.layers[base_name][(annotation_type, layer_subtype_id)] = layer
+        return layer_subtype_id
 
     def set_metadata(self, metadata: Dict[str, str]):
         if not self.metadata: