Returns the number of days in the coupon period that contains the settlement date.
| Name | Type | Description |
| arg1 | any | Is the security's settlement date, expressed as a serial date number. |
| arg2 | any | Is the security's maturity date, expressed as a serial date number. |
| arg3 | any | Is the number of coupon payments per year. |
| arg4 | any | Is the type of day count basis to use. |