Passing a string to ExecuteProcess arguments behaves unintuitively

In Node constructor, arguments takes an arguments of list of strings. Passing a string to arguments typechecks but provides unexpected results, treating the string as a sequence of single-character arguments.

e.g the following code:

    driver_node = LifecycleNode(package='ros2_ouster',
                                node_executable='ouster_driver',
                                node_name=node_name,
                                output='screen',
                                emulate_tty=True,
                                parameters=[parameter_file],
                                node_namespace='/',
                                arguments='__log_level:=debug'
                                )

This displays no error message but the mistake is visible when the process dies.

[ERROR] [ouster_driver-1]: process has died [pid 309341, exit code -15, cmd '/opt/ros/master/install/lib/ros2_ouster/ouster_driver _ _ l o g _ l e v e l : = d e b u g --ros-args -r __node:=ouster_driver --params-file /opt/ros/master/install/share/ros2_ouster/params/os1.yaml -r __ns:=/'].

Passing a string to arguments (or similar places) should either:

1. Split the string on spaces
2. Alert the user (ArgumentError seems apt)