Returns the discount rate for a security.
| 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 security's price per $100 face value. |
| arg4 | any | Is the security's redemption value per $100 face value. |
| arg5 | any | Is the type of day count basis to use. |