fix playback_file

playback_file.py

@@ -216,7 +216,7 @@ if __name__ == '__main__':
     SUBID = int(cli_args.SUBID)
     if 'ONESHOT' in cli_args:
         ONESHOT = bool(cli_args.ONESHOT)
-    if 'INTERVAL' in cli_args and int(cli_args.INTERVAL) > 30:
+    if 'INTERVAL' in cli_args and cli_args.INTERVAL and int(cli_args.INTERVAL) > 30:
         INTERVAL = int(cli_args.INTERVAL)
     if 'TALKGROUP' in cli_args:
         TALKGROUP = int(cli_args.TALKGROUP)