Write a PL/SQL procedure to accepts a BOOLEAN parameter and uses a CASE statement to print Unknown if the value of the parameter is NULL, Yes if it is TRUE, and No if it is FALSE

CREATE PROCEDURE use_of_boolean (bl BOOLEAN) AUTHID DEFINER
AS
BEGIN
  DBMS_OUTPUT.put_line (
    CASE
      WHEN bl IS NULL THEN 'Unknown'
      WHEN bl THEN 'Yes'
      WHEN NOT bl THEN 'No'
    END
  );
END;
/
BEGIN
  use_of_boolean(NULL);
  use_of_boolean(FALSE);
  use_of_boolean(TRUE);
END;
/

Sample Output: