Function FoundSheet(AWB As Workbook, ByRef ASheetCodeName As String) As Worksheet
Dim AWS As Worksheet
Set FoundSheet = Nothing
For Each AWS In AWB.Sheets
If UCase(AWS.CodeName) = UCase(ASheetCodeName) Then
Set FoundSheet = AWS
Exit Function
End If
Next
End Function

Function CreateOrAssignMyList(ByRef AWB As Workbook) As Worksheet
Dim N%
Set CreateOrAssignStatList = FoundSheet AWB "MyList"
if CreateOrAssignStatList is Nothing then Exit Function
AWB.Sheets.Add Before:=AWB.Sheets(1)
Set CreateOrAssignStatList = AWB.Sheets(1)
If CreateOrAssignStatList Is Nothing Then Exit Function
.......
End Function

sub Test
dim ws As Worksheet
set ws = CreateOrAssignList(Thisworkbook)
end sub