fix channel name assertion

iobber/chunker.py

@@ -37,8 +37,8 @@ from operator import itemgetter as ig
 
 def get_layers(conf):
 	layers = [(k, v.split(',')) for (k, v) in conf.items(config.S_LAYERS)]
-	for layer in layers:
-		assert '-' not in layer, 'hyphens are not allowed in channel names'
+	for name, _ in layers:
+		assert '-' not in name, 'hyphens are not allowed in channel names'
 	return layers
 
 def is_input_tagged(conf):