VBA Error handling, define an Error into an Error - vba

Question

I launch Python through a VBA macro. I want a proper error message if the Python path isn't good.
I use this macro on 2 different computers, and the Python paths are not the same on those 2 computers. The 2 paths are on 2 differents Cells name path_Python and path_Python_2
Here is my code :
Function launchPython() As Boolean
Dim pathScript As String
pathScript = [path_files] + "code.py"
On Error GoTo err
Shell [path_Python].Value & " " & pathScript
launchPython = True
Exit Function
err:
On Error GoTo err2
Shell [path_Python_2].Value & " " & pathScript
launchPython = True
err2:
launchPython = False
MsgBox "Error: please check Python paths"
End Function
Problem is, when 2 the paths are not good, instead of going to err2, I have a VBA error message blocking on
err:
On Error GoTo err2
Shell [path_Python_2].Value & " " & pathScript
How can I solve this ?
Thank you very much

Answer 1

Instead of trying to shell a command to a potentially missing path, I would check that a file exists and try that. You can use one of many functions such as FileExists in http://allenbrowne.com/func-11.html, or just check that dir$ returns non blank.
Dim Path as string
path = path_python
if dir(path) = "" then
path = path_python2
if dir(path) = "" then err.raise
end if
shell path & " " & pathScript