How to handle None with mysql.connector

[verb]

Hello everyone, Can anyone advice how to handle empty string or None when insert data in mysql integer column.
Here is the code i have:

import mysql.connector
cnx = mysql.connector.connect(user='user',
                                  password='pass',
                                  host='192.168.18.1',
                                  database='db')
data = None
conn = cnx.cursor()
conn.execute("insert into contract(red) values('{}')".format(data))
cnx.commit()

and here is the otput :

mysql.connector.errors.DataError: 1366 (22007): Incorrect integer value: 'None' for column 'red' at row 1

Problem is that i don't know when the data would be integer or None.