diff --git a/swh/loader/git/loader.py b/swh/loader/git/loader.py
--- a/swh/loader/git/loader.py
+++ b/swh/loader/git/loader.py
@@ -10,7 +10,7 @@
 import os
 import pickle
 import sys
-from typing import Any, Dict, Iterable, Optional
+from typing import Any, Dict, Iterable, List, Optional, Union
 
 import dulwich.client
 from dulwich.object_store import ObjectStoreGraphWalker
@@ -33,7 +33,7 @@
         self.storage = storage
 
         self._parents_cache = {}
-        self._type_cache = {}
+        self._type_cache: Dict[bytes, TargetType] = {}
 
         self.ignore_history = ignore_history
 
@@ -136,7 +136,27 @@
 
         return list(ret)
 
-    def get_stored_objects(self, objects):
+    def _get_stored_objects_batch(
+            self, query
+            ) -> Dict[bytes, List[Dict[str, Union[bytes, TargetType]]]]:
+        results = self.storage.object_find_by_sha1_git(
+            self._encode_for_storage(query)
+        )
+        ret: Dict[bytes, List[Dict[str, Union[bytes, TargetType]]]] = {}
+        for (id, objects) in results.items():
+            assert id not in ret
+            ret[id] = [
+                {
+                    'sha1_git': obj['sha1_git'],
+                    'type': TargetType(obj['type']),
+                }
+                for obj in objects
+            ]
+        return ret
+
+    def get_stored_objects(
+            self, objects
+            ) -> Dict[bytes, List[Dict[str, Union[bytes, TargetType]]]]:
         """Find which of these objects were stored in the archive.
 
         Do the request in packets to avoid a server timeout.
@@ -146,23 +166,15 @@
 
         packet_size = 1000
 
-        ret = {}
+        ret: Dict[bytes, List[Dict[str, Union[bytes, TargetType]]]] = {}
         query = []
         for object in objects:
             query.append(object)
             if len(query) >= packet_size:
-                ret.update(
-                    self.storage.object_find_by_sha1_git(
-                        self._encode_for_storage(query)
-                    )
-                )
+                ret.update(self._get_stored_objects_batch(query))
                 query = []
         if query:
-            ret.update(
-                self.storage.object_find_by_sha1_git(
-                    self._encode_for_storage(query)
-                )
-            )
+            ret.update(self._get_stored_objects_batch(query))
         return ret
 
     def find_remote_ref_types_in_swh(
@@ -176,12 +188,14 @@
         """
 
         all_objs = set(remote_refs.values()) - set(self._type_cache)
-        type_by_id = {}
+        type_by_id: Dict[bytes, TargetType] = {}
 
         for id, objs in self.get_stored_objects(all_objs).items():
             id = hashutil.hash_to_bytehex(id)
             if objs:
-                type_by_id[id] = objs[0]['type']
+                type_ = objs[0]['type']
+                assert isinstance(type_, TargetType)
+                type_by_id[id] = type_
 
         self._type_cache.update(type_by_id)