diff --git a/wf/script.py b/wf/script.py
index 47dc0bb..db78c79 100755
--- a/wf/script.py
+++ b/wf/script.py
@@ -348,15 +348,15 @@ def find_project_by_id(project_data, target_id): # {{{
# }}}
-def show(parent_id, flat=False, filter_all=[], filter_any=[], color="grey"): # {{{
+def show(parent_id, flat=False, filter_all=None, filter_any=None, color="grey"): # {{{
root_data = load_from_storage("root")
project_data = find_project_by_id(root_data, parent_id)
project_data = simplify_project(project_data)
if flat:
project_data = flatten_project(project_data)
- if filter_all is not []:
+ if filter_all is not None:
pass
- if filter_any is not []:
+ if filter_any is not None:
project_data = filter_project_any(project_data, filter_any)
project_data = strip(project_data, r".*")
project_data = strip(project_data, r"