def METHOD_NAME(
    admin_client, edit_link, theme, default_theme
):
    admin_client.post(edit_link, {"name": theme.name, "parent": default_theme.pk})
    default_theme.refresh_from_db()
    theme.refresh_from_db()
    assert theme.tree_id == default_theme.tree_id
    assert theme.lft == 2
    assert theme.rght == 3
    assert default_theme.lft == 1
    assert default_theme.rght == 4