python contains Chinese string length

Python contains the length of Chinese strings

A Chinese utf8 encoding occupies 3 characters, so the function to find the length can be written like this

def str_len(str):
    try:
        row_l=len(str)
        utf8_l=len(str.encode('utf-8'))
        return (utf8_l-row_l)/2+row_l
    except:
        return None
    return None