diff --git a/lib/global_id/locator.rb b/lib/global_id/locator.rb
index 71687a3..f4dec07 100644
--- a/lib/global_id/locator.rb
+++ b/lib/global_id/locator.rb
@@ -141,8 +141,8 @@ def locate_many(gids, options = {})
           end
 
           records_by_model_name_and_id = {}
-          ids_by_model.each do |model, ids|
 
+          ids_by_model.each do |model, ids|
             records = find_records(model, ids, ignore_missing: options[:ignore_missing])
 
             records_by_id = records.index_by do |record|
@@ -164,12 +164,8 @@ def find_records(model_class, ids, options)
             end
           end
 
-          private
           def model_id_is_valid?(gid)
-            primary_key = Array(gid.model_class.primary_key)
-            primary_key_size = primary_key.size
-
-            Array(gid.model_id).size == primary_key_size
+            Array(gid.model_id).size == Array(gid.model_class.primary_key).size
           end
       end