diff --git a/djangotoolbox/db/base.py b/djangotoolbox/db/base.py
index ab7b9ab..165510f 100644
--- a/djangotoolbox/db/base.py
+++ b/djangotoolbox/db/base.py
@@ -476,7 +476,7 @@ def _value_for_db_collection(self, value, field, field_kind, db_type,
                     for subvalue in value)
 
                 # "list" may be used for SetField.
-                if db_type in 'list':
+                if db_type == 'list':
                     return list(value)
                 elif db_type == 'set':
                     # assert field_kind != 'ListField'