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 Ref_document_types (document_type_code VARCHAR, document_type_name VARCHAR)
### Question:
What is the document type code for document type "Paper"?
### Answer:
SELECT document_type_code FROM Ref_document_types WHERE document_type_name = "Paper"