Python题目不会！求帮助！

Question

Answer 1

def translate(string):
    if string==string.lower():
        string=string.upper()
    elif string==string.upper():
        string=string.lower()
    return string

translate('HAHA')
'haha'
translate('heihei')
'HEIHEI'
translate('HoHo')
'HoHo'
translate('Want 100')
'Want 100'