Added a utility to join lists of items as strings with comma/and separation

src/common.py

@@ -1,14 +1,32 @@
 import os
 import streamlit as st
 
+from typing import List
+
 
 data_dir = os.path.join(os.path.dirname(__file__), '..', 'data')
 img_dir = os.path.join(os.path.dirname(__file__), '..', 'img')
 config_dir = os.path.join(os.path.dirname(__file__), '..', 'config')
 
+
 def hf_api_token() -> str:
-    #TODO: Need to consider how to make this more generic to look for a token elsewhere
+    """
+    Utility single access point to look up the hugging face access token.
+    """
     token = st.secrets['hf_token']
     if token is None:
         raise ValueError('No HF access token found in streamlit secrets')
     return token
+
+
+def join_items_lowercased_comma_and(items: List[str]) -> str:
+    """
+    Utility to convert a list of items to lowercase strings, comma separated and ending with and
+    """
+    items = [str(i).lower().strip() for i in items]
+    string_count = len(items)
+    if string_count == 0:
+        return ""
+    if string_count == 1:
+        return items[0]
+    return f"{', '.join(items[:-1])} and {items[-1]}"