Settle Date
Function Settle Date within Bond with keys Bond Settle Date keysreturns the settlement date Tˢ of the referenced bond associated with the given reference date T₀ when a bond trade (transaction) takes place.
Several values may be also returned here in the form of a 1D-array
If the settlement date Tˢ is not explicitly given, it will be set to the bond's settlement date as implied by a trade transaction assumed to occur on the trade dateT₀ (typically today).
