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_17641206_4 (directed_by VARCHAR, written_by VARCHAR)
### Question:
Who was the director when the writer was John Sullivan?
### Answer:
SELECT directed_by FROM table_17641206_4 WHERE written_by = "John Sullivan"