Return related terms when no results are found

app.py

@@ -1,3 +1,5 @@
+import difflib
+
 from collections import Counter
 import streamlit as st
 import pandas as pd
@@ -31,14 +33,22 @@ if "grants" not in st.session_state:
 
 grants = st.session_state["grants"]
 
+if "tags" not in st.session_state:
+    st.session_state["tags"] = list(set([tag for grant in grants for tag in grant["tags"]]))
+
+tags = st.session_state["tags"]
+
 query = st.text_input("", value="Malaria")
 st.button("Search 🔎", on_click=search, kwargs={"query": query})
 
 if "results" in st.session_state:
     st.caption("Related MeSH terms")
 
-    retrieved_tags = [tag for res in st.session_state["results"] for tag in res["tags"]]
-    most_common_tags = [tag for tag, _ in Counter(retrieved_tags).most_common(20)]
+    if st.session_state["results"]:
+        retrieved_tags = [tag for res in st.session_state["results"] for tag in res["tags"]]
+        most_common_tags = [tag for tag, _ in Counter(retrieved_tags).most_common(20)]
+    else:
+        most_common_tags = difflib.get_close_matches(query, tags, n=20)
 
     columns = st.columns(5)
     for row_i in range(3):