The method GetByID returns the discount parameters.
||The ID of the discount whose parameters are to be returned.
Associated array of the discount parameters; has the following keys.
||The discount ID.
||The ID of the site to which this discount is bound.
||Minimum total order price to which this discount is applicable.
||Maximum total order price to which this discount is applicable.
||Currency in which all money values are specified in this record.
||Type of the discount value (P - percentage, V - absolute
||Flag indicating the discount is active (Y/N).
||Sort weight. If more than one discount can be applied to an order price,
the discount with the less SORT is taken first.