Question about Knowledge Base Action

Doc : Knowledge Base Actions

Hi rasa community , i new to rasa and i just read up on this experimental feature which quite interesting. Woud like to ask for example in shell :

Your input → do you know the price range of that one
‘Lụa Restaurant (Vietnamese)’ has the value ‘cheap’ for attribute ‘price-range’. // *For this line

For the 2nd line in shell , what should i do to implement in the to have my bot make use of the domain knowledge attribute to generate proper string response to user just like the example shown in doc .

To add-on : What is the best method to implement a retail-voice assistant , should i use the Json or database method for knowledge base . Currently i looking to use this KBA to implement for rasa to awnser question to user on certain product (example A Phone specification with or without 3.5mm jack,etc)

You can add corpus to cover the second one.

Sorry I think there is a misunderstood from my question , I would like to modify the domain knowledge response to a proper string just like example showing in the doc