from llama_index.indices.query.query_transform import HyDEQueryTransform
from llama_index.query_engine.transform_query_engine import (
    TransformQueryEngine,
)

index = VectorStoreIndex.from_documents(documents, service_context=service_context_gpt3)
query_engine = index.as_query_engine(similarity_top_k=3)

hyde = HyDEQueryTransform(include_original=True)
hyde_query_engine = TransformQueryEngine(query_engine, hyde)