diff --git a/libmat2/archive.py b/libmat2/archive.py
index f6db491..48c1594 100644
--- a/libmat2/archive.py
+++ b/libmat2/archive.py
@@ -372,7 +372,8 @@ class ZipParser(ArchiveBasedAbstractParser):
 
     def is_archive_valid(self):
         try:
-            zipfile.ZipFile(self.filename)
+            with zipfile.ZipFile(self.filename):
+                pass
         except zipfile.BadZipFile:
             raise ValueError
 
diff --git a/mat2 b/mat2
index 3ff6d95..857996e 100755
--- a/mat2
+++ b/mat2
@@ -13,8 +13,8 @@ import concurrent.futures
 try:
     from libmat2 import parser_factory, UNSUPPORTED_EXTENSIONS
     from libmat2 import check_dependencies, UnknownMemberPolicy
-except ValueError as e:
-    print(e)
+except ValueError as ex:
+    print(ex)
     sys.exit(1)
 
 __version__ = '0.12.2'