Concatenate an array of strings with commas and a final “and”, or other separators

' Concatenate an array of strings with commas and a final "and",'  or other separators'' Example:'   Debug.WriteLine("Choose one from " & CreateStringList(New String() {"item1",'  "item2", "item3"}))'   ' => Choose one from item1, item2 and item3Function CreateStringList(ByVal items() As String, Optional ByVal sep As String _    = ", ", Optional ByVal lastSep As String = " and ") As String    ' join the strings with the first separator    Dim res As String = String.Join(sep, items)    ' find the last occurrence of the separator used to join the strings,    '  remove it and insert the last separator instead    Dim i As Integer = res.LastIndexOf(sep)    If i > -1 Then        res = res.Remove(i, sep.Length)        res = res.Insert(i, lastSep)    End If    Return resEnd Function