Caught the exception when the there are zero documents returned.

public_app.py

@@ -68,6 +68,9 @@ def get_chain(query, api_key=os.environ['OPENAI_API_KEY']):
                    ' If you believe this is wrong, please flag below as appropriate.'
         filtered_context = search_with_filter(vs, query, init_k=200, step=500, target_k=7, filter_dict=filter_date)
         logging.info(20 * '-' + 'Metadata for the documents to be used' + 20 * '-')
+        if len(filtered_context) == 0:
+            return 'There is no information in the minutes for the given date. Please check if there were was an FOMC ' \
+                   'meeting  on the given date. If you believe this is wrong, please flag below as appropriate.'
         for doc in filtered_context:
             logging.info(doc.metadata)
     return fed_chain({'input_documents': filtered_context[:7], 'question': query})['output_text']