handle items without audios

thanks for fuzzing me, radioblackout.org

feed

@@ -297,10 +297,14 @@ def get_urls_generic(tree, url_selector="description[text()]", metadata_in_body=
                 audio.date = get_item_date(it)
             yield audio
         else:
-            url = it.xpath(url_selector)[0]
-            audio = Audio(url)
-            audio.date = get_item_date(it)
-            yield audio
+            try:
+                url = it.xpath(url_selector)[0]
+            except IndexError:
+                logging.warn("no audio found in %s", title)
+            else:
+                audio = Audio(url)
+                audio.date = get_item_date(it)
+                yield audio
 
 
 def get_urls_from_podcast(tree):