Inpsect python-launchfile related variables at runtime in ROS 2

edit

Let's say I have the following launchfile (from the nav2_bringup repo):

def generate_launch_description():
    map_yaml_file = launch.substitutions.LaunchConfiguration('map')
    use_sim_time = launch.substitutions.LaunchConfiguration('use_sim_time', default='false')

    return LaunchDescription([
        launch.actions.DeclareLaunchArgument(
            'map', description='Full path to map file to load'),
        launch.actions.DeclareLaunchArgument(
            'use_sim_time', default_value='false', description='Use simulation (Gazebo) clock if true'),

        launch_ros.actions.Node(
            package='nav2_map_server',
            node_executable='map_server',
            node_name='map_server',
            output='screen',
            parameters=[{ 'use_sim_time': use_sim_time}, { 'yaml_filename': map_yaml_file }]),

        launch_ros.actions.Node(
            package='nav2_amcl',
            node_executable='amcl',
            node_name='amcl',
            output='screen',
            parameters=[{ 'use_sim_time': use_sim_time}]),
])

How can I debug such launchfile, meaning, how can I at runtime inspect the values of the launch arguments or the values of the substitution parameters?

AFAIK you can't just use pdb, since their values depend on the 'LaunchContext' which is not available before returning from this method, right?

Any suggestion?