Analysis toolpack functions in VBA

Dim holidayDictionary As Object

Sub LoadHolidays()
    If (holidayDictionary Is Nothing) Then
        Set holidayDictionary = CreateObject("Scripting.Dictionary")
        holidayDictionary.Add #7/4/2007#, Null
        'more holidays can be entered here
    End If
End Sub

Function ISHOLIDAY(d As Date)
    LoadHolidays
    ISHOLIDAY = holidayDictionary.Exists(d)
End Function

Function ISWORKDAY(d As Date)

    Dim weekday As Integer
    weekday = DatePart("w", d, vbUseSystemDayOfWeek, vbUseSystem)

    If ((weekday = vbSaturday) Or (weekday = vbSunday)) Then
        ISWORKDAY = False
    Else
        ISWORKDAY = Not ISHOLIDAY(d)
    End If
End Function

Function NEXTTRADEDAY(d As Date, numOfDays As Integer) As Double
    'Set holidayDictionary = Nothing
    LoadHolidays
    NEXTTRADEDAY = Application.WorksheetFunction.WorkDay(d, numOfDays, holidayDictionary.Keys)
End Function