fix error output

1 files changed, 1 insertions, 1 deletions

diff --git a/l6/kod.py b/l6/kod.py
index 060dc21..1bf5ea3 100644
--- a/l6/kod.py
+++ b/l6/kod.py
@@ -32,7 +32,7 @@ def eval_expression(frame, statement):
         return statement
     elif calc.isvariable(statement):
         if statement not in frame:
-            print("variable {} not declared", statement)
+            print("variable {} not declared".format(statement))
             sys.exit(-1)
         return frame[statement]
     elif calc.isbinary(statement):