Solve All Upper I

Hello! Can anyone help me to determine a mistake in "Solve All Upper I":

def is_all_upper(text: str) -> bool:
    if text != (""):  
        a=text.isupper()
        return (a)
    else:
        return True

if __name__ == '__main__':
    print("Example:")
    print(is_all_upper(''))

It looks like all answers are correct, but when i try to check it:

Your result:False Right result:True Fail:isallupper(" ")