Find the model name of my robot

edit

Hello,

its a bit embarrassing but i just cant find anything on it. So i m trying to write a program that randomizes the initial pose of the robot and i found a bit of code online that was super helpful but at some line they ask for :

state_msg.model_name = 'my_robot'

which i guessed i have to change "my_robot" to the model name of the robot i am using but i dont know where i can find it. is there a rostopic that outputs the model name of a robot in gazebo or can i find it anywhere else?