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 table_2226817_4 (written_by VARCHAR, original_air_date VARCHAR)
### Question:
Name who wrote the episode that aired april 9, 1989
### Answer:
SELECT written_by FROM table_2226817_4 WHERE original_air_date = "April 9, 1989"