diff --git a/neuralmonkey/run.py b/neuralmonkey/run.py
index 469e37410..7753b3649 100644
--- a/neuralmonkey/run.py
+++ b/neuralmonkey/run.py
@@ -147,5 +147,5 @@ def main() -> None:
         if eval_result:
             print_final_evaluation(dataset.name, eval_result)
 
-    while len(CONFIG.model.tf_manager.sessions):
+    for _ in range(len(CONFIG.model.tf_manager.sessions)):
         del CONFIG.model.tf_manager.sessions[0]