fixed up clusters

backend/src/overpass/overpass.py

@@ -39,6 +39,8 @@ def build_query(area: tuple, element_types: ElementTypes, selector: str,
     """
     if not isinstance(conditions, list) :
         conditions = [conditions]
+    if not isinstance(element_types, list) :
+        element_types = [element_types]
 
     query = '('
 
@@ -60,7 +62,7 @@ def build_query(area: tuple, element_types: ElementTypes, selector: str,
     return query
 
 
-def send_overpass_query(query: str, use_cache: bool = True) -> dict:
+def send_overpass_query(query: str) -> dict:
     """
     Sends the Overpass QL query to the Overpass API and returns the parsed JSON response.
 
@@ -76,7 +78,7 @@ def send_overpass_query(query: str, use_cache: bool = True) -> dict:
 
     # Try to fetch the result from the cache
     cached_response = CachingStrategy.get(cache_key)
-    if cached_response:
+    if cached_response is not None :
         print("Cache hit!")
         return cached_response