Update models/langOpen.py

Added from langchain.retrievers import ContextualCompressionRetriever
from langchain.retrievers.document_compressors import CohereRerank
from langchain_community.llms import Cohere

models/langOpen.py

@@ -9,6 +9,10 @@ from langchain.embeddings import OpenAIEmbeddings
 from langchain.prompts import PromptTemplate
 from langchain_pinecone import PineconeVectorStore
 
+from langchain.retrievers import ContextualCompressionRetriever
+from langchain.retrievers.document_compressors import CohereRerank
+from langchain_community.llms import Cohere
+
 prompt_template = """You are an expert on California Drinking Water Regulations.
 Answer the question solely using relevant regulations in the given context. DO NOT USE ANY OTHER SOURCES.
 If the given context does not contain the relevant information, say so.