remove redundant check.

Author: WaVEV

django_mongodb/compiler.py

@@ -475,26 +475,23 @@ def get_combinator_queries(self):
         if not parts:
             raise EmptyResultSet
         combinator_pipeline = parts.pop(0)[0].get_pipeline()
-        if self.query.combinator == "union":
-            for part, collection in parts:
-                combinator_pipeline.append(
-                    {"$unionWith": {"coll": collection, "pipeline": part.get_pipeline()}}
-                )
-                if not self.query.combinator_all:
-                    ids = {}
-                    for alias, expr in main_query_columns:
-                        # Unfold foreign fields.
-                        if isinstance(expr, Col) and expr.alias != self.collection_name:
-                            ids[self._unfold_column(expr)] = expr.as_mql(self, self.connection)
-                        else:
-                            ids[alias] = f"${alias}"
-                    combinator_pipeline.append({"$group": {"_id": ids}})
-                    projected_fields = self._fold_columns(ids)
-                    combinator_pipeline.append({"$addFields": projected_fields})
-                    if "_id" not in projected_fields:
-                        combinator_pipeline.append({"$unset": "_id"})
-        else:
-            raise NotSupportedError(f"Combinator {self.query.combinator} isn't supported.")
+        for part, collection in parts:
+            combinator_pipeline.append(
+                {"$unionWith": {"coll": collection, "pipeline": part.get_pipeline()}}
+            )
+            if not self.query.combinator_all:
+                ids = {}
+                for alias, expr in main_query_columns:
+                    # Unfold foreign fields.
+                    if isinstance(expr, Col) and expr.alias != self.collection_name:
+                        ids[self._unfold_column(expr)] = expr.as_mql(self, self.connection)
+                    else:
+                        ids[alias] = f"${alias}"
+                combinator_pipeline.append({"$group": {"_id": ids}})
+                projected_fields = self._fold_columns(ids)
+                combinator_pipeline.append({"$addFields": projected_fields})
+                if "_id" not in projected_fields:
+                    combinator_pipeline.append({"$unset": "_id"})
         return combinator_pipeline
 
     def get_lookup_pipeline(self):