text: 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_72 (sleeves VARCHAR, back VARCHAR)
  ### Question:
  Which Sleeves have a Back of Unknown?
  ### Answer:
  SELECT sleeves FROM table_name_72 WHERE back = "unknown"