diff --git a/auto_cache.py b/auto_cache.py
index 81ace62..9ded114 100644
--- a/auto_cache.py
+++ b/auto_cache.py
@@ -22,7 +22,7 @@ def auto_cache_data():
     today = datetime.date.today()
     print(today)
     for item in items:
-        prev_day = today.deltaday(-1)
+        prev_day = today.timedelta(days=-1)
         str_prev_day = prev_day.strftime('%Y-%m-%d')
         print(str_prev_day)
         key = item.replace('[DATE]', str_prev_day)