Handle edge case with zero (active) meetings

bbbmon/bbbmon.py

@@ -140,7 +140,11 @@ def get_meetings(secret: Secret, bbb_url: Url) -> Iterable[XmlDictConfig]:
     if type(d["meetings"]["meeting"]) is XmlListConfig:
         meetings = sorted([m for m in d["meetings"]["meeting"] if m["running"] == "true"], key=lambda x:int(x['participantCount']), reverse=True)
     elif type(d["meetings"]["meeting"]) is XmlDictConfig:
+        if len(d["meetings"]["meeting"]) > 0:
             meetings = [d["meetings"]["meeting"][0]]
+        else:
+            print("There are no active meetings currently.")
+            exit()
     return meetings