diff --git a/pisi/zipfileext.py b/pisi/zipfileext.py
index 6a587fe2..0878a73a 100644
--- a/pisi/zipfileext.py
+++ b/pisi/zipfileext.py
@@ -1,7 +1,41 @@
-# extends zipfile module with 7zip support
+# -*- coding: utf-8 -*-
+#
+# Copyright (C) 2006, TUBITAK/UEKAE
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation; either version 2 of the License, or (at your option)
+# any later version.
+#
+# Please read the COPYING file.
+#
+# Authors:  Eray Ozkural <eray@pardus.org.tr>
+#           Faik Uygur   <faik@pardus.org.tr>
+#
+# Extends zipfile module with 7zip and bzip2 support
+
+# python standard library modules
+import os
+import struct
+import time
 
 from zipfile import *
 
+try:
+    import zlib
+except ImportError:
+    zlib = None
+
+try:
+    import bzip2
+except ImportError:
+    bzip2 = None
+
+try:
+    import pylzma
+except ImportError:
+    pylzma = None
+
 ZIP_BZIP2 = 12
 ZIP_7ZIP = 255