(num, default)
return default
check if the format of number is (num)(G|m|B) i.e 500GB, 200mb. 400
        etc..
check if the format of number is (num)(G|m|B) i.e 500GB, 200mb. 400
        etc..
check if the format of number is ( num ) ( G|m|B ) i . e 500GB 200mb . 400 etc ..
def get_valid_byte(num, default):
        """check if the format of number is (num)(G|m|B) i.e 500GB, 200mb. 400
        etc.. """
        num_valid = re.match(r"\A([0-9]+)(M|G|m|g|)(B|b|\b)\Z", num, re.I)
        if num_valid:
            return num
        return default
def get_valid_byte ( num , default ) : num_valid = re . match ( r"\A([0-9]+)(M|G|m|g|)(B|b|\b)\Z" , num , re . I ) if num_valid : return num return default