Calculate Working Days With Oracle Function

how do i can make oracle function for the following vb6 function.

This function is used for calculating working days between two date.

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Public Function Work_Days(BegDate As Variant, EndDate As Variant) As Integer

' Note that this function does not account for holidays.

Dim WholeWeeks As Variant
Dim DateCnt As Variant
Dim EndDays As Integer

On Error GoTo Err_Work_Days
BegDate = DateValue(BegDate)
EndDate = DateValue(EndDate)
WholeWeeks = DateDiff("w", BegDate, EndDate)
DateCnt = DateAdd("ww", WholeWeeks, BegDate)
[code]......