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_10592536_8 (date_of_appointment VARCHAR, date_of_vacancy VARCHAR)
### Question:
What is the date of appointment when the date of vacancy is 21 december 2007?
### Answer:
SELECT date_of_appointment FROM table_10592536_8 WHERE date_of_vacancy = "21 December 2007"