L3-Chains notebook cell 39 is failing

Hi Team,
I am working on L3-Chains note book and cell 39 is failing with the following error, can you please help me fix this:

Entering new MultiPromptChain chain…
biology: {‘input’: ‘Why does every cell in our body contain DNA?’}


ValueError Traceback (most recent call last)
Cell In[39], line 1
----> 1 chain.run(“Why does every cell in our body contain DNA?”)

File /usr/local/lib/python3.9/site-packages/langchain/chains/base.py:236, in Chain.run(self, callbacks, *args, **kwargs)
234 if len(args) != 1:
235 raise ValueError(“run supports only one positional argument.”)
→ 236 return self(args[0], callbacks=callbacks)[self.output_keys[0]]
238 if kwargs and not args:
239 return self(kwargs, callbacks=callbacks)[self.output_keys[0]]

File /usr/local/lib/python3.9/site-packages/langchain/chains/base.py:140, in Chain.call(self, inputs, return_only_outputs, callbacks)
138 except (KeyboardInterrupt, Exception) as e:
139 run_manager.on_chain_error(e)
→ 140 raise e
141 run_manager.on_chain_end(outputs)
142 return self.prep_outputs(inputs, outputs, return_only_outputs)

File /usr/local/lib/python3.9/site-packages/langchain/chains/base.py:134, in Chain.call(self, inputs, return_only_outputs, callbacks)
128 run_manager = callback_manager.on_chain_start(
129 {“name”: self.class.name},
130 inputs,
131 )
132 try:
133 outputs = (
→ 134 self._call(inputs, run_manager=run_manager)
135 if new_arg_supported
136 else self._call(inputs)
137 )
138 except (KeyboardInterrupt, Exception) as e:
139 run_manager.on_chain_error(e)

File /usr/local/lib/python3.9/site-packages/langchain/chains/router/base.py:86, in MultiRouteChain._call(self, inputs, run_manager)
84 return self.default_chain(route.next_inputs, callbacks=callbacks)
85 else:
—> 86 raise ValueError(
87 f"Received invalid destination chain name ‘{route.destination}’"
88 )

ValueError: Received invalid destination chain name ‘biology’

Yeah, I got this error too. What I did to try and solve the problem is modifying the MULTI_PROMPT_ROUTER_TEMPLATE. I added this line after the REMEMBER section to the prompt and it worked as intended.

" MAKE SURE THAT THE DESTINATION IS ONE OF THE CANDIDATE PROPMTS, SEE IF IT IS INCLUDED IN THE LIST OF DESTINATIONS BEFORE SELECTING IT AND IF IT IS NOT, THEN SELECT “DEFAULT”. "

And for some weird reason, it doesn’t work when it is lower case, it only does like the format above (All Uppercase).

Hope this Helps :blush:

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