Pre-defining an action to take when an expected error occurs

[Tempo]

Thanks for all of the help. It all has been very useful to an new
python programmer. I agree that I should fix the error/bug instead of
handeling it with a try/etc. However, I do not know why
"range(sh.nrows)" never gets the right amount of rows right. For
example, if the Excel sheet has 10 rows with data in them, the
statement "range(sh.nrows)" should build the list of numbers [0,
1,...9]. It should, but it doesn't do that. What it does is buld a list
from [0, 1...20] or more or a little less, but the point is that it
always grabs empy rows after the last row containing data. Why is that?
I have no idea why, but I do know that that is what is producing the
error I am getting. Thanks again for the responses that I have received
already, and again thanks for any further help. Thanks you.