Which contact channel has been used by the customer with name "Tillman Ernser"?
SELECT DISTINCT channel_code FROM customers AS t1 JOIN customer_contact_channels AS t2 ON t1.customer_id  =  t2.customer_id WHERE t1.customer_name  =  "Tillman Ernser"
SELECT DISTINCT channel_code FROM customers AS t1 JOIN customer_contact_channels AS t2 ON t1.customer_id  =  t2.customer_id WHERE t1.customer_name  =  "Tillman Ernser"
[{'channel_code': 'Email'}, {'channel_code': 'Cell'}, {'channel_code': 'Handheld'}]