VBA underscore trouble

Hello,

I wrote a simple VBA code which is pretty long, so I want to use a underscore to continue on the next line.

Here is an example of the code:
Sub Mergeing()
Sheets("blad1").Range("A1:B1,A2: B2 ").Merge
End Sub

In the actual code I have a lot more cells I want to merge.

this is what I want to do:
Sub Mergeing()
Sheets("blad1").Range("a1:a3, _
b1: b3 ").Merge
End Sub

When I do this, I get a compiling error telling me to input a separator.

What am I doing wrong?
I thought a space followed by an underscore was enough to continue on the next line.

Please let me know what to do.

Best regards,
Trowa