diff --git a/trademark/lib/poiskznakov.py b/trademark/lib/poiskznakov.py
index 49ad5f5..5afafe4 100644
--- a/trademark/lib/poiskznakov.py
+++ b/trademark/lib/poiskznakov.py
@@ -36,9 +36,11 @@ class TrademarkSearchAPI():
             'databases': [21, 23],
             'use_translit': 'true',
             'skip_expired': 'true',
-            'icgs': [int(nice) for nice in nices.split(',')]
         }
 
+        if nices:
+            request['icgs'] = [int(nice) for nice in nices.split(',')]
+
         if similarity < 100:
             request['search_method'] = 'similarity'
             request['minimum_similarity'] = similarity