What are the names of customers who do not have any policies?
SELECT customer_details FROM customers EXCEPT SELECT t2.customer_details FROM policies AS t1 JOIN customers AS t2 ON t1.customer_id  =  t2.customer_id
SELECT customer_details FROM customers EXCEPT SELECT t2.customer_details FROM policies AS t1 JOIN customers AS t2 ON t1.customer_id  =  t2.customer_id
[{'Customer_Details': 'Augustine Kerluke'}, {'Customer_Details': 'Ellsworth Paucek'}, {'Customer_Details': 'Mr. Edwardo Blanda I'}, {'Customer_Details': 'Mr. Randal Lynch III'}, {'Customer_Details': 'Sydnie Friesen'}]