Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE CLASS (class_code VARCHAR, class_room VARCHAR)
### Question:
List the codes of all courses that take place in room KLR209.
### Answer:
SELECT class_code FROM CLASS WHERE class_room = 'KLR209'