From bcf0fd6029d67f0bde834909d92f0194a72afc28 Mon Sep 17 00:00:00 2001
From: Shy <shy@koeln.ccc.de>
Date: Tue, 21 Mar 2017 12:08:00 +0100
Subject: [PATCH] Make a copy of mutable list in pull()

---
 c4ctrl.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/c4ctrl.py b/c4ctrl.py
index 58013f0..c140a68 100755
--- a/c4ctrl.py
+++ b/c4ctrl.py
@@ -62,7 +62,7 @@ class C4Interface():
     def pull(self, topic=[]):
         """Return current state of topic."""
         from paho.mqtt import subscribe
-        topic = topic or self.topic
+        topic = topic.copy() or self.topic
         # <topic> must be a list
         if type(topic) == str:
             topic = [topic]
@@ -1047,7 +1047,7 @@ if __name__ == "__main__":
     if args.k_switch != None:
         Keller().light_switch(args.k_switch)
 
-    # No command line options or only debug?
+    # No or no useful command line options?
     if len(sys.argv) <= 1 or len(sys.argv) == 2 and args.debug:
         parser.print_help()