diff --git a/python/knext/knext/operator/op.py b/python/knext/knext/operator/op.py
index 8ea7d867c..2fa315736 100644
--- a/python/knext/knext/operator/op.py
+++ b/python/knext/knext/operator/op.py
@@ -10,7 +10,7 @@
 # is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 # or implied.
 from abc import ABC
-from typing import List, Dict, Any
+from typing import List, Dict, Tuple, Any
 
 import knext.common.cache
 from knext.common.schema_helper import SPGTypeName, TripletName
@@ -27,7 +27,9 @@ class ExtractOp(BaseOp, ABC):
     def __init__(self, params: Dict[str, str] = None):
         super().__init__(params)
 
-    def invoke(self, record: Dict[str, str]) -> List[Dict[str, str]]:
+    def invoke(
+        self, record: Dict[str, str]
+    ) -> Tuple[List[Dict[str, str]], List[SPGRecord]]:
         raise NotImplementedError(
             f"{self.__class__.__name__} need to implement `invoke` method."
         )
diff --git a/python/knext/knext/operator/spg_record.py b/python/knext/knext/operator/spg_record.py
index 391add896..62819d466 100644
--- a/python/knext/knext/operator/spg_record.py
+++ b/python/knext/knext/operator/spg_record.py
@@ -16,6 +16,7 @@
     SPGTypeName,
     PropertyName,
     RelationName,
+    SPGTypeHelper,
 )
 
 
@@ -170,6 +171,10 @@ def upsert_relation(
         :param value: The updated relation value.  # noqa: E501
         :type: str
         """
+        if isinstance(self._spg_type_name, SPGTypeHelper):
+            if not hasattr(self._spg_type_name, str(relation_name)):
+                raise KeyError(f"Relation {relation_name} not defined in Schema")
+
         self.relations[relation_name + "#" + object_type_name] = value
         return self
 
@@ -181,7 +186,7 @@ def upsert_relations(self, relations: Dict[Tuple[RelationName, SPGTypeName], str
         :type: dict
         """
         for (relation_name, object_type_name), value in relations.items():
-            self.relations[relation_name + "#" + object_type_name] = value
+            self.upsert_relation(relation_name, object_type_name, value)
         return self
 
     def remove_relation(
@@ -204,7 +209,7 @@ def remove_relations(self, relation_names: List[Tuple[RelationName, SPGTypeName]
         :param relation_names: A list of relation names.  # noqa: E501
         :type: list
         """
-        for (relation_name, object_type_name) in relation_names:
+        for relation_name, object_type_name in relation_names:
             self.relations.pop(relation_name + "#" + object_type_name)
         return self