Update app.py

app.py

@@ -3,6 +3,13 @@ import langchain
 # https://huggingface.co/spaces/joyson072/LLm-Langchain/blob/main/app.py
 from langchain.llms import HuggingFaceHub
 
+
+# for the chain and prompt
+from langchain.prompts import PromptTemplate
+from langchain.llms import HuggingFaceHub
+from langchain.chains import LLMChain
+
+
 # https://colab.research.google.com/drive/1hrS6_g14EcOD4ezwSGlGX2zxJegX5uNX#scrollTo=NUwUR9U7qkld
 llm_hf = HuggingFaceHub(
     repo_id="OpenAssistant/oasst-sft-4-pythia-12b-epoch-3.5",