Performs a knowledge base lookup, and returns a list of the knowledge chunks it found as a result.

The content template becomes the query that will be sent up to the knowledge base to match against.

Options

`query_transformation_chain`	This specifies which smart-chain will be used to transform the content you provide into the query that will be matched against within the knowledge base. By default its `knowledge_base_identity_query_transformer` which just applies no transformation
`reranking_chain`	This specifies which smart-chain will be used to compute a reranking score on the results. By default its `knowledge_base_identity_reranker` which just applies no reranking
`filtering_chain`	This specifies which smart-chain will be used to filter the knowledge-base results.

Output

`knowledge_chunks`	A list containing the top-20 matching knowledge chunks found in the knowledge base. Each knowledge chunk has the following fields:
	`matching_text` - This is the text associated with the knowledge chunk which is used to match against the users query. In the default configuration, the matching_text is in the form of a question.
	`qualifying_text` - This is a bit of text that provides contextual information needed to determine if this knowledge chunk is relevant or not. In the default configuration, the qualifying_text is just a summary of the document where the knowledge came from.
	`content_text` - This is the main text of the knowledge chunk that contains the knowledge we retrieved. This is usually some snippet of text that was isolated and separated from the larger document it was apart of.
	`originating_object_id` - This is the ID of the object that this knowledge chunk was derived from, such as an imported web-page or imported PDF document