diff --git a/seminar/treelib.py b/seminar/treelib.py
index 946e61fd..8cf01660 100644
--- a/seminar/treelib.py
+++ b/seminar/treelib.py
@@ -18,13 +18,17 @@ def safe_pred(node):
 	except ObjectDoesNotExist:
 		return None
 
+def first_brother(node):
+	brother = node
+	while safe_pred(brother) is not None:
+		brother = safe_pred(brother)
+	return brother
+
 # A to samé pro .father_of_first
 def safe_father_of_first(node):
-	first_brother = node
-	while safe_pred(first_brother) is not None:
-		first_brother = safe_pred(first_brother)
+	first = first_brother(node)
 	try:
-		return first_brother.father_of_first
+		return first.father_of_first
 	except ObjectDoesNotExist:
 		return None