[ROS2] extend env vars in launch file instead of overwriting

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Hey all,

Is it possible to somehow extend environment instead of overwriting them in a launch file? I need something like this (https://github.com/ros2/launch/issues...) :

SetEnvironmentVariable(name='PATH', value=[EnvironmentVariable('PATH'), '/some/other/bin']

But unfortunately appending is not supported yet EnvironmentVariable gives an error.

It seems to be possible to do it with ExecuteProcess based on this discussion but I do not want to start my node like this even if it is possible.
ExecuteProcess(cmd=cmd, additional_env=env, output='screen')

Also ExecuteProcess(cmd=['export', 'LD_LIBRARY_PATH=<NEW_PATH>:$LD_LIBRARY_PATH'], output='screen'), does not work.

Thanks in advance.