How to modify the argument in launch file by using python?

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I want to use the python to modify the argument in launch file,

 <node pkg="kompi_tasks" name="listener" type="receivedname_pro.py" respawn="false" output="screen" />

Firstly, I have run the node to received a name, this name is as an variable, then I want to pass this name from python to launch file, and as an argument to launch the following file.

<arg name="robot_global_name" default="false" />

For example, I want to change the value of default to an variable from python.

How can I do this?