diff --git a/pycromanager/acquisition/java_RAMStorage.py b/pycromanager/acquisition/java_RAMStorage.py
index b44a1b5b..439c5abd 100644
--- a/pycromanager/acquisition/java_RAMStorage.py
+++ b/pycromanager/acquisition/java_RAMStorage.py
@@ -13,7 +13,7 @@ def __init__(self, java_RAM_data_storage):
         self._java_RAM_data_storage = java_RAM_data_storage
         self._index_keys = set()
 
-    def _add_index_entry(self, data):
+    def add_index_entry(self, data):
         self._index_keys.add(frozenset(data.items()))
 
     # def get_channel_names(self):