diff --git a/src/ifcopenshell-python/ifcopenshell/geom/app.py b/src/ifcopenshell-python/ifcopenshell/geom/app.py
index b4099ee9cc..43d5762584 100644
--- a/src/ifcopenshell-python/ifcopenshell/geom/app.py
+++ b/src/ifcopenshell-python/ifcopenshell/geom/app.py
@@ -615,7 +615,7 @@ class application(QtWidgets.QApplication):
 
         return handler
 
-    def __init__(self, settings={}):
+    def __init__(self, settings=None):
         QtWidgets.QApplication.__init__(self, sys.argv)
         self.window = application.window()
         self.tree = application.decomposition_treeview()
diff --git a/src/ifcopenshell-python/ifcopenshell/geom/main.py b/src/ifcopenshell-python/ifcopenshell/geom/main.py
index 062fc2c980..e8040d2814 100644
--- a/src/ifcopenshell-python/ifcopenshell/geom/main.py
+++ b/src/ifcopenshell-python/ifcopenshell/geom/main.py
@@ -124,7 +124,7 @@ class iterator(_iterator):
 
 
 class tree(ifcopenshell_wrapper.tree):
-    def __init__(self, file=None, settings={}):
+    def __init__(self, file=None, settings=None):
         args = [self]
         if file is not None:
             args.append(file.wrapped_data)