def open(host: str, usr: str, passwd: str, db_name: str):
    conn = pymysql.connect(host=host, user=usr, password=passwd, db=db_name, charset='utf8', cursorclass=pymysql.cursors.DictCursor)
    return conn
def open(host: str, usr: str, passwd: str, db_name: str):
    conn = pymysql.connect(host=host, user=usr, password=passwd, db=db_name, charset='utf8', cursorclass=pymysql.cursors.DictCursor)
    return conn