Parent is now mandatory when creating a new BaseInstance class

src/app.py

@@ -7,7 +7,7 @@ from myfasthtml.controls.Layout import Layout
 from myfasthtml.controls.TabsManager import TabsManager
 from myfasthtml.controls.helpers import Ids, mk
 from myfasthtml.core.commands import Command
-from myfasthtml.core.instances import InstancesManager
+from myfasthtml.core.instances import InstancesManager, RootInstance
 from myfasthtml.myfastapp import create_app
 
 with open('logging.yaml', 'r') as f:
@@ -27,10 +27,10 @@ app, rt = create_app(protect_routes=True,
 
 @rt("/")
 def index(session):
-  layout = InstancesManager.get(session, Ids.Layout, Layout, "Testing Layout")
+  layout = InstancesManager.get(session, Ids.Layout, Layout, RootInstance, "Testing Layout")
   layout.set_footer("Goodbye World")
   
-  tabs_manager = TabsManager(session, _id="main")
+  tabs_manager = TabsManager(layout, _id=f"{Ids.TabsManager}-main")
   
   btn_show_right_drawer = mk.button("show",
                                     command=Command("ShowRightDrawer",