diff --git a/zz-extra/lxc-pack b/zz-extra/lxc-pack
index 41ca130..8fd8ce5 100755
--- a/zz-extra/lxc-pack
+++ b/zz-extra/lxc-pack
@@ -15,7 +15,7 @@ BUILD_ROOT = '/root/buildroot'
 LXC_ROOT = '/var/lib/lxc'
 
 def pack(pkg_file):
-    if os.path.is_dir(pkg_file):
+    if os.path.isdir(pkg_file):
         pkg_file = os.path.join(pkg_file, 'pkg')
     # Prepare metadata
     meta = {}