VBA: test if workbook is nothing - vba

Question

Edit: My real question is how to test if object was set that was instantiated. I am not really looking to "correct" my code. Its just an example.
I have a function that returns a workbook:
Edit: Added code
Sub GetWb() as Workbook
Application.DisplayAlerts = False
Application.EnableEvents = False
On Error Resume Next
Set wM = Application.Workbooks.Open("Z:\somepath.xlsm", ReadOnly:=True)
Application.EnableEvents = True
Application.DisplayAlerts = True
On Error GoTo 0
end sub
In another sub I want to check if that object was set properly by the function. I usually do something like this with objects generally:
dim w as Workbook
set w = GetWb
if w is nothing then
debug.print "no workbook"
else
debug.print "workbook"
end if
However, the is nothing test does not work because the object is instantiated, but was not set so it is something, not nothing.
I have resorted to this ugly solution, which works fine:
dim w as Workbook
set w = GetWb
on error goto someerrorhandling
if w.name = "" then
end if
on error goto 0
'other code here
someerrorhandling:
msgbox "no workbook"
In other words, I check a property of the object to force an error, or not. There must be a better/cleaner way.
I checked and this link states that the way I am doing it is the best way:
VBA: Conditional - Is Nothing

Answer 1

change your error handling for GetWB so it returns nothing incase of error, also use Function instead of sub.
Function GetWb() As Workbook
Application.DisplayAlerts = False
Application.EnableEvents = False
On Error GoTo errHandler:
Set GetWb = Application.Workbooks.Open("Z:\somepath.xlsm", ReadOnly:=True)
Application.EnableEvents = True
Application.DisplayAlerts = True
errHandler:
If Err.Number <> 0 Then
Set GetWb = Nothing
Application.EnableEvents = True
Application.DisplayAlerts = True
End If
End Function