diff --git a/kerchunk/grib2.py b/kerchunk/grib2.py
index 120e8992..86cd5769 100644
--- a/kerchunk/grib2.py
+++ b/kerchunk/grib2.py
@@ -1,7 +1,8 @@
 import base64
 import logging
 from collections import defaultdict
-from typing import Iterable, List, Dict, Set
+
+# from typing import Iterable, List, Dict, Set
 
 import ujson
 
@@ -361,11 +362,11 @@ def example_combine(
 
 
 def grib_tree(
-    message_groups: Iterable[Dict],
-    concat_dims: List[str],
-    identical_dims: List[str],
+    message_groups,
+    concat_dims,
+    identical_dims,
     remote_options=None,
-) -> Dict:
+):
     """
     Create a single zarr hierarchy from a grib file with multiple levels. MultiZarrToZarr aggregation requires
     picking filters for a particular set of GRIB levels. This method allows reading an entire grib file into
@@ -393,8 +394,8 @@ def grib_tree(
     zroot = zarr.open_group(store=zarr_store)
     result = dict(refs=zarr_store)
 
-    aggregations: Dict[str, List] = defaultdict(list)
-    aggregation_dims: Dict[str, Set] = defaultdict(set)
+    aggregations = defaultdict(list)
+    aggregation_dims = defaultdict(set)
 
     unknown_counter = 0
     for msg_ind, group in enumerate(message_groups):