Seemingly same values do not return true when compared

Question

I'm building an application in python using tkinter. Have put an KeyPress eventListener (from tkinter), the event gets triggered as it should, but when checking the keycode/keysym of the event things don't go as expected:

window.bind("<KeyPress>", onkeydown)

def onkeydown(e): 
    print(e.keysym is "Return")
    print(e.keycode is 13)
    print(e.keycode, e.keysym)

Console output:
False
False
13 Return

this is a serious thread, can anyone explain whats going on here?