What was the production code of the episode written by Anthony Sparks?
CREATE TABLE table_25851971_1 (
    production_code VARCHAR,
    written_by VARCHAR
)
SELECT production_code FROM table_25851971_1 WHERE written_by = "Anthony Sparks"
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: What was the production code of the episode written by Anthony Sparks? ### Input: CREATE TABLE table_25851971_1 (
    production_code VARCHAR,
    written_by VARCHAR
) ### Response: SELECT production_code FROM table_25851971_1 WHERE written_by = "Anthony Sparks"