Could not process parameters: int(20), it must be of type list, tuple or dict

#coding: utf-8

from mysql.connector import connect,pooling

config = {
    "host": "localhost",
    "port": 3306,
    "user": "root",
    "password": "123456abc",
    "database": "demo"
}

try:
    pool = pooling.MySQLConnectionPool(**config, pool_size=3)
    con = pool.get_connection()
    con.start_transaction()
    cursor = con.cursor()
    sql = "DELETE e,d FROM t_emp e JOIN t_dept d ON e.deptno=d.deptno WHERE d.deptno=%s;"
    cursor.execute(sql,(20))
    con.commit()

except Exception as e:
    if "con" in dir():
        con.rollback()
    print(e)

执行后有一条提示信息：

Could not process parameters: int(20), it must be of type list, tuple or dict

不明白这个提示信息是怎么回事。