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_22347090_6 (written_by VARCHAR, production_code VARCHAR)
### Question:
Who wrote the episode that has a production code 3x7557?
### Answer:
SELECT written_by FROM table_22347090_6 WHERE production_code = "3X7557"