ProductId
Type defines a product identifier. The product ID is an identifier that describes
the key economic characteristics of the trade type, with the exception of concepts
such as size (notional, quantity, number of units) and price (fixed rate, strike,
etc.) that are negotiated for each transaction. FpML does not define the domain values
associated with this type. Note that the domain values for this type are not strictly
an enumerated list.
External values enumeration.