Is there any documentation or advice giving guidance to migrating existing Ignition Gazebo examples to use ros_gz.

Sample 1) Gazebo Simulation (https://automaticaddison.com/set-up-the-odometry-for-a-simulated-mobile-robot-in-ros-2/) installs ros-humble-gazebo-rospkgs and a launch file includes this code, that uses the gazeboros_packages executables, as illustrated below..

-# Specify the actions

-# Start Gazebo server startgazeboservercmd = IncludeLaunchDescription( PythonLaunchDescriptionSource(os.path.join(pkggazeboros, 'launch', 'gzserver.launch.py')), condition=IfCondition(usesimulator), launch_arguments={'world': world}.items())

X-Start Gazebo client
startgazeboclientcmd = IncludeLaunchDescription( PythonLaunchDescriptionSource(os.path.join(pkggazeboros, 'launch', 'gzclient.launch.py')), condition=IfCondition(PythonExpression([usesimulator, ' and not ', headless])))

Sample 2) Example of of a wheeled robot design, where the Gazebo-Classic Package gazeboros is used. This is an extract from its launchsim.launch.py showing the part that launches Classic Gazebo:

---

import os

from amentindexpython.packages import getpackageshare_directory

from launch import LaunchDescription from launch.actions import IncludeLaunchDescription from launch.launchdescriptionsources import PythonLaunchDescriptionSource

from launch_ros.actions import Node

def generatelaunchdescription():

[:launch robotstatepublisher, joystick, etc]

gazeboparamsfile = os.path.join(getpackagesharedirectory(packagename),'config','gazebo_params.yaml')

# Include the Gazebo launch file, provided by the gazebo_ros package
gazebo = IncludeLaunchDescription(
            PythonLaunchDescriptionSource([os.path.join(
                get_package_share_directory('gazebo_ros'), 'launch', 'gazebo.launch.py')]),
                launch_arguments={'extra_gazebo_args': '--ros-args --params-file ' + gazebo_params_file}.items()
         )

# Run the spawner node from the gazebo_ros package. The entity name doesn't really matter if you only have a single robot.
spawn_entity = Node(package='gazebo_ros', executable='spawn_entity.py',
                    arguments=['-topic', 'robot_description',
                               '-entity', 'my_bot'],
                    output='screen')

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A spawned node is started from the gazeboros package with executable “spawnentity.py” .

Any suggested Gazebo Garden rosgz code would replace the gzserver, gclient, and spawnentity code?