diff --git a/libqmpbackup/image.py b/libqmpbackup/image.py
index 8eb85cb..9b04d59 100644
--- a/libqmpbackup/image.py
+++ b/libqmpbackup/image.py
@@ -161,7 +161,7 @@ def _check(image):
 
 
 def _snapshot_exists(snapshot, image):
-    """before rebase we check consistency of all files"""
+    """before rebase we check if an snapshot already exists"""
     check_cmd = f"qemu-img snapshot -l '{image}'"
     try:
         log.info(check_cmd)
diff --git a/libqmpbackup/vm.py b/libqmpbackup/vm.py
index 3e44827..2186840 100644
--- a/libqmpbackup/vm.py
+++ b/libqmpbackup/vm.py
@@ -11,7 +11,6 @@
  the LICENSE file in the top-level directory.
 """
 
-import os
 import json
 import logging
 from dataclasses import dataclass