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_name_4 (fastest_lap VARCHAR, winning_driver VARCHAR, date VARCHAR)
### Question:
Who had the fastest lap of the race that Ayrton Senna won on 23 April?
### Answer:
SELECT fastest_lap FROM table_name_4 WHERE winning_driver = "ayrton senna" AND date = "23 april"