I know there's a similar topic about python console, but I do not know if they are the same. I tried system("clear") and it didn't work here.
How do I clear python's IDLE window?
The "cls" and "clear" are commands which will clear a terminal (ie a DOS prompt, or terminal window). From your screenshot, you are using the shell within IDLE, which won't be affected by such things. Unfortunately, I don't think there is a way to clear the screen in IDLE. The best you could do is to scroll the screen down lots of lines, eg:
print "\n" * 100
Though you could put this in a function:
def cls(): print "\n" * 100
And then call it when needed as