Defines a settlement as an exchange between two parties of a specified quantity of an asset (the quantity) against a specified quantity of another asset (the price). The settlement is optional and can be either cash or physical. The quantity can additionally be specified in terms of one or more currency amounts. In the case of non-cash products, the settlement of the price/quantity would not be specified here and instead would be delegated to the product mechanics, as parameterised by the price/quantity values.