diff --git a/django/db/models/query.py b/django/db/models/query.py
index 73af5f54dd..6d3acef703 100644
--- a/django/db/models/query.py
+++ b/django/db/models/query.py
@@ -667,7 +667,7 @@ def get_cached_row(klass, row, index_start):
 def fill_table_cache(opts, select, tables, where, old_prefix, cache_tables_seen):
     """
     Helper function that recursively populates the select, tables and where (in
-    place) for fill-cache queries.
+    place) for select_related queries.
     """
     for f in opts.fields:
         if f.rel and not f.null:
@@ -688,6 +688,7 @@ def fill_table_cache(opts, select, tables, where, old_prefix, cache_tables_seen)
 def parse_lookup(kwarg_items, opts):
     # Helper function that handles converting API kwargs
     # (e.g. "name__exact": "tom") to SQL.
+    # Returns a tuple of (tables, joins, where, params).
 
     # 'joins' is a sorted dictionary describing the tables that must be joined
     # to complete the query. The dictionary is sorted because creation order