diff --git a/u3/skatule.py b/u3/skatule.py
index d7b38fa..2c632e0 100644
--- a/u3/skatule.py
+++ b/u3/skatule.py
@@ -4,7 +4,9 @@ def flatten(iterable):
     r = []
     for i in iterable:
         if(type(i) is list):
-            r.extend(flatten(i))
+            if(i is not None):
+                r.extend(flatten(i))
         else:
-            r.append(i)
+            if(i is not None):
+                r.append(i)
     return r
\ No newline at end of file