> I'm not sure.

The output I provided above as ```master``` is **the** correct one. I pointed **incorrect** to my code conversion, but nothing with ```master``` code. i.e. ```atoms(Symbol)```.

> Please don't add just references to master. You should actually understand what this code does, not just guess based on master's output.

No. I understood the code usage in ```sympy.polys.constructor.py``` where it took app. 2 hours. I have given the reason in the above comment. If you are still unclear I am ready to explain.