Settle Prd

Function Settle Prd within Bondreturns the settlement period of the referenced bond expressed as an object of type Single Period
Several values may be also returned here in the form of a 1D-array
The financial interpretation is that if a bond trade (transaction) takes place on some settlement date Tˢ, the agreed cash amount is paid (settled) at Tˢ + PRD, where PRD is the period returned here.