Adding Collision Objects MoveIt! python

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I am trying to add my CAD model(.stl format) as a collision object for UR robot to do some trajectories by avoiding the added objects. I see only the methods using C++ but not with python. Where do I place the CAD file and what do I need to call from the code. I tried placing the file under meshes/ur10e/collision. But it didn't work. I am running ROS Melodic.

I found the below question but with the defined method it didn't work. I need to know where do I place the file and how do I set the size if my CAD file already has the dimensions. https://answers.ros.org/question/2090...