i don't know, what i doing wrong....

def checkio(data):
    its_digit ,its_lower ,its_upper = (False,False,False)
    if len(data) >= 10:
        for el in data:
             if el.upper():
                its_upper = True
             if el.lower():
                its_lower = True
             if el.isdigit():
                its_digit = True
    return its_digit and its_lower and its_upper and (len(data)>= 10)

I can't pass 6th test, where : - Your result: true; - Fail : checkio("6691219721"); - Right result: false; - length ≥ 10;