diff --git a/src/_zkapauthorizer/_storage_client.py b/src/_zkapauthorizer/_storage_client.py
index 6ebd3ccebf793203b06ec99303293f2108d88eb9..1add745801a8ebaded010f0b937a7d3d54eae336 100644
--- a/src/_zkapauthorizer/_storage_client.py
+++ b/src/_zkapauthorizer/_storage_client.py
@@ -387,7 +387,7 @@ class ZKAPAuthorizerStorageClient(object):
                 None,
             )
         ).values()
-        num_passes = required_passes(self._pass_value, list(share_sizes))
+        num_passes = required_passes(self._pass_value, share_sizes)
 
         result = yield call_with_passes(
             lambda passes: rref.callRemote(
diff --git a/src/_zkapauthorizer/storage_common.py b/src/_zkapauthorizer/storage_common.py
index 5313b315d3b5c83aec42f2ff615e512d631a66e5..34360810d439c53a4336df8ab0d8dc2b7b82b575 100644
--- a/src/_zkapauthorizer/storage_common.py
+++ b/src/_zkapauthorizer/storage_common.py
@@ -254,7 +254,7 @@ def get_required_new_passes_for_mutable_write(pass_value, current_sizes, tw_vect
     """
     current_passes = required_passes(
         pass_value,
-        list(current_sizes.values()),
+        current_sizes.values(),
     )
 
     new_sizes = current_sizes.copy()