TypeError: unsupported operand type(s) for -: 'datetime.datetime' and 'NoneType'

[ciaran-regan-ie]

System Info

langchain version 0.0.171 python version 3.9.13

macos

Who can help?

No response

Information

• [X] The official example notebooks/scripts
• [ ] My own modified scripts

Related Components

• [ ] LLMs/Chat Models
• [ ] Embedding Models
• [ ] Prompts / Prompt Templates / Prompt Selectors
• [ ] Output Parsers
• [ ] Document Loaders
• [ ] Vector Stores / Retrievers
• [X] Memory
• [X] Agents / Agent Executors
• [ ] Tools / Toolkits
• [ ] Chains
• [ ] Callbacks/Tracing
• [ ] Async

Reproduction

This is a problem with the generative agents.

To reproduce please follow the tutorial outlines here: https://python.langchain.com/en/latest/use_cases/agent_simulations/characters.html

When you get to the following line of code you will get an error: print(tommie.get_summary(force_refresh=True))

File ~/.pyenv/versions/3.9.13/lib/python3.9/site-packages/langchain/retrievers/time_weighted_retriever.py:14, in _get_hours_passed(time, ref_time)
12 def _get_hours_passed(time: datetime.datetime, ref_time: datetime.datetime) -> float:
13 """Get the hours passed between two datetime objects."""
---> 14 return (time - ref_time).total_seconds() / 3600

TypeError: unsupported operand type(s) for -: 'datetime.datetime' and 'NoneType'

Expected behavior

The ref time should be a datetime and tommies summary should be printed.

[zhyjiong]

same issue

[bear96]

Same issue

[LouisSilva]

Same issue

[vanakema]

Same issue

[arttukataja]

same issue

[alfred-liu96]

It was caused by the parameter now.

There are sevaral functions in the GenerativeAgent and GenerativeAgentMemory class that are needed to fill in the parameter now, such as add_memory, generate_dialogue_response or generate_reaction. It is optional but without filling it, errors like above will occur.

I think it shoud be changed to required or default to be datatime.datetime.now()

[bear96]

It was caused by the parameter now.

There are sevaral functions in the GenerativeAgent and GenerativeAgentMemory class that are needed to fill in the parameter now, such as add_memory, generate_dialogue_response or generate_reaction. It is optional but without filling it, errors like above will occur.

I think it shoud be changed to required or default to be datatime.datetime.now()

I agree. I found that this now is an optional parameter which takes the value of None if not specified. Every time I add a memory, the creation time becomes none. So it wasn't working..