add date to date_str var in template formatting

chain.py

@@ -100,7 +100,7 @@ class ChainBuilder:
         # Prompt Template for generation
         prompt = ChatPromptTemplate.from_messages(
             [
-                ("system", self.llm_config.get("llm_prompt_template")),
+                ("system", self.llm_config.get("llm_prompt_template").format(date_str=datetime.datetime.now().strftime("%B %d, %Y"))), # add current date to the date_str var in system prompt
                 # *** Note: This chain does not compress the history, so very long converastions can overflow the context window. TODO
                 # We need to at some point chop this history down to fixed amount of recent messages
                 MessagesPlaceholder(variable_name="formatted_chat_history"),
@@ -184,7 +184,6 @@ class ChainBuilder:
                 | RunnableLambda(self.format_context), 
                 "formatted_chat_history": itemgetter("formatted_chat_history"),
                 "question": itemgetter("question"),
-                "date_str": RunnableLambda(get_date), # date to be passed to system prompt for context of when knowledge base was last updated
             }
             | self.get_prompt() # 'context', 'formatted_chat_history', and 'question' passed to prompt
             | self.get_model() # prompt passed to model