def of_retriever(retriever: VectorStoreRetriever, **kwargs: Any):
        """
        Create a new instance of WithFeedbackFilterDocuments based on an existing retriever.

        The new instance will:

        1. Get relevant documents (like the existing retriever its based on).
        2. Evaluate documents with a specified feedback function.
        3. Filter out documents that do not meet the minimum threshold.

        Args:
            retriever: VectorStoreRetriever - the base retriever to use.

            **kwargs: additional keyword arguments.

        Returns:
        - WithFeedbackFilterDocuments: a new instance of WithFeedbackFilterDocuments.
        """
        return WithFeedbackFilterDocuments(
            **kwargs, **(serial_utils.model_dump(retriever))
        )

        Create a new instance of WithFeedbackFilterDocuments based on an existing retriever.

        The new instance will:

        1. Get relevant documents (like the existing retriever its based on).
        2. Evaluate documents with a specified feedback function.
        3. Filter out documents that do not meet the minimum threshold.

        Args:
            retriever: VectorStoreRetriever - the base retriever to use.

            **kwargs: additional keyword arguments.

        Returns:
        - WithFeedbackFilterDocuments: a new instance of WithFeedbackFilterDocuments.
        
src/apps/langchain/trulens/apps/langchain/guardrails.py