Vertexai express mode API support in langchain

I want to ask is langchain (either langchain_google_genai or langchain_google_vertexai) supported to use API of vertexai express mode already? Because I can’t find it in the documentation.
According to vertexai documentation (https://docs.cloud.google.com/vertex-ai/generative-ai/docs/start/express-mode/vertex-ai-express-mode-api-quickstart) we can use Vertex ai express mode api to use the LLM.
Thank you.