Reject time parameters that are not datetime, date or string

src/cal_tools/calcat_interface2.py

@@ -57,6 +57,11 @@ class CalCatAPIClient:
             return dt.astimezone(timezone.utc).isoformat()
         elif isinstance(dt, date):
             return cls.format_time(datetime.combine(dt, time()))
+        elif not isinstance(dt, str):
+            raise TypeError(
+                f"Timestamp parameter ({dt!r}) must be a string, datetime or "
+                f"date object"
+            )
 
         return dt