What is causing the error in my multimodal query engine?

# Initialize the multimodal query engines
query_engine = MultimodalQueryEngine(
    retriever=index.as_retriever(similarity_top_k=3),
    multi_modal_llm=azure_openai_mm_llm,  # Use Azure GPT-4V for multimodal understanding
)

base_query_engine = MultimodalQueryEngine(
    retriever=baseline_index.as_retriever(similarity_top_k=3),
    multi_modal_llm=azure_openai_mm_llm,  # Use Azure GPT-4V for multimodal understanding
)

# Example usage: Try a query with text and image understanding
response = query_engine.custom_query("Describe the content and key insights from the provided slides.")
print(str(response))

class MultimodalQueryEngine(CustomQueryEngine):
    """Custom multimodal Query Engine."""

    def __init__(self, retriever, multi_modal_llm, qa_prompt=None):
        super().__init__(retriever=retriever, qa_prompt=qa_prompt or QA_PROMPT)
        # Explicitly define multi_modal_llm as a class attribute
        self.multi_modal_llm = multi_modal_llm

    def custom_query(self, query_str: str):
        # Retrieve text nodes
        nodes = self.retriever.retrieve(query_str)
        # Create ImageNode items from text nodes
        image_nodes = [
            NodeWithScore(node=ImageNode(image_path=n.metadata["image_path"]))
            for n in nodes
        ]

        # Create context string from text nodes
        context_str = "\n\n".join(
            [n.node.get_content(metadata_mode=MetadataMode.LLM) for n in nodes]
        )
        fmt_prompt = self.qa_prompt.format(context_str=context_str, query_str=query_str)

        # Synthesize an answer using AzureOpenAIMultiModal for image and text understanding
        llm_response = self.multi_modal_llm.complete(
            prompt=fmt_prompt,
            image_documents=[image_node.node for image_node in image_nodes],
        )
        return Response(
            response=str(llm_response),
            source_nodes=nodes,
            metadata={"text_nodes": nodes, "image_nodes": image_nodes},
        )