diff --git a/hw5/ooc.py b/hw5/ooc.py
index 3325331..6465e7f 100644
--- a/hw5/ooc.py
+++ b/hw5/ooc.py
@@ -81,7 +81,7 @@ class MemoryLimitedHashMap(object):
     key = k.split("_")[0]
     return key
 
-  def flushKey(self, k, subkey):
+  def flushKey(self, k, subkey=""):
     '''
     Removes the key from the dictionary and 
     persists it to disk.