diff --git a/django/db/models/query.py b/django/db/models/query.py
index a8ab94d013..fa3969ecfc 100644
--- a/django/db/models/query.py
+++ b/django/db/models/query.py
@@ -195,10 +195,7 @@ class QuerySet(object):
     ##################################################
 
     def in_bulk(self, id_list):
-        try:
-            iter(id_list)
-        except TypeError:
-            assert False, "in_bulk() must be provided with a list of IDs."
+        assert isinstance(id_list, (tuple,  list)), "in_bulk() must be provided with a list of IDs."
         id_list = list(id_list)
         assert id_list != [], "in_bulk() cannot be passed an empty ID list."
         return self._clone(klass=InBulkQuerySet, _id_list=id_list)