How to use memory_limit_number and preference_limit_number in memory search function?

[audreycs]

Hi, I want to know how memory_limit_number and preference_limit_number parameters control the returned memory results of search_memory function. According to the document, memory_limit_number limits the number of fact memory items returned and preference_limit_number limits the number of preference memory items returned. But I find when setting preference_limit_number=6, the returned results don't contain any preference memory:

res = self.client.search_memory(
          query=query, 
          user_id=user_id, 
          conversation_id=conversation_id,
          memory_limit_number = 6,
          include_preference = True,
          preference_limit_number = 6
          )

The only practice I tried that can produce preference memory is when setting memory_limit_number much bigger than preference_limit_number, such as memory_limit_number=15 and preference_limit_number=6.

Any help is appreciated. Thanks!