INTERFACE {{p}}if_trade_in PUBLIC.
  TYPES ty_value TYPE i.
  TYPES ty_brand TYPE c LENGTH 8.
  TYPES ty_grade TYPE c LENGTH 1.
  TYPES ty_reason TYPE c LENGTH 10.
  TYPES:
    BEGIN OF ty_result,
      amount TYPE ty_value,
      reason TYPE ty_reason,
    END OF ty_result.
  CONSTANTS:
    BEGIN OF c_brand,
      premium TYPE ty_brand VALUE 'PREMIUM',
      volume  TYPE ty_brand VALUE 'VOLUME',
      budget  TYPE ty_brand VALUE 'BUDGET',
    END OF c_brand,
    BEGIN OF c_grade,
      a TYPE ty_grade VALUE 'A',
      b TYPE ty_grade VALUE 'B',
      c TYPE ty_grade VALUE 'C',
      d TYPE ty_grade VALUE 'D',
    END OF c_grade,
    BEGIN OF c_reason,
      ok      TYPE ty_reason VALUE 'OK',
      brand   TYPE ty_reason VALUE 'BRAND',
      grade   TYPE ty_reason VALUE 'GRADE',
      age     TYPE ty_reason VALUE 'AGE',
      mileage TYPE ty_reason VALUE 'MILEAGE',
    END OF c_reason.
  METHODS assess
    IMPORTING iv_brand      TYPE ty_brand
              iv_grade      TYPE ty_grade
              iv_age_months TYPE i
              iv_mileage    TYPE i
    RETURNING VALUE(rs_result) TYPE ty_result.
ENDINTERFACE.