what is single underscore and double underscore in python,what is there differences?

Answer 1

https://stackoverflow.com/questions/1301346/what-is-the-meaning-of-a-single-and-a-double-underscore-before-an-object-name?_e_pi_=7%2CPAGE_ID10%2C5142026986

Answer 2

I need more detailed clear difference.. thanks