Function: `DateDiff`

Returns the numeric difference in the requested date part between two dates

Method Signature

DateDiff(datepart=[string], date1=[any], date2=[any])

Argument	Type	Required	Description
`datepart`	`string`	`true`
`date1`	`any`	`true`	The reference date object
`date2`	`any`	`true`	The date which to compare against date1