Simplify list handling

stechuhr_client/client.py

@@ -290,7 +290,7 @@ def read_key_input(input_queue, config, logger):
 
     # Buffer to store incoming keys till ENTER (keycode 28) is received
     keybuffer = []
-    last_seen_cards = None
+    last_seen_cards = []
 
     # Loop Forever over the Input
     while True:
@@ -320,7 +320,7 @@ def read_key_input(input_queue, config, logger):
 
 
 
-                    if last_seen_cards is None or len(last_seen_cards) == 0:
+                    if len(last_seen_cards) == 0:
                         input_queue.put(joined_string)
                         last_seen_cards.append({"id": joined_string, "time": time.time()})
                     else: