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_28652521_1 (singer_part_number VARCHAR, storage_case VARCHAR)
### Question:
What's the singer part number of the buttonholer whose storage case is a green plastic box?
### Answer:
SELECT singer_part_number FROM table_28652521_1 WHERE storage_case = "green plastic box"