We can insert a row in the tree column (the first column) by using the insert method and passing in the text.
self.treeview_cars.insert(parent="",
index=tk.END,
text="Mini Van")
We can insert values under Mini Van so when it expands, it reveals more information.
# Get the parent item iid
mini_van_iid = self.treeview_cars.insert(parent="",
index=tk.END,
text="Mini Van")
# Add a vehicle under Mini Van
self.treeview_cars.insert(parent=mini_van_iid,
index=tk.END,
values=("Toyota", "2024"))