diff --git a/pisi/cli/commands.py b/pisi/cli/commands.py
index 6b0f22d6..47081830 100644
--- a/pisi/cli/commands.py
+++ b/pisi/cli/commands.py
@@ -775,7 +775,7 @@ expanded to package names.
                     packages.extend(ctx.componentdb.get_union_packages(name, walk=True))
         packages.extend(self.args)
 
-        if packages = []:
+        if packages == []:
             packages = ctx.installdb.list_installed()
 
         if ctx.get_option('exclude_from'):