How to guard against bugs like this one?

[John Nagle]

kj wrote:
...
> 
> Through a *lot* of trial an error I finally discovered that the
> root cause of the problem was the fact that, in the same directory
> as buggy.py, there is *another* innocuous little script, totally
> unrelated, whose name happens to be numbers.py. 

    The right answer to this is to make module search return an
error if two modules satisfy the search criteria.  "First find"
isn't a good solution.

				John Nagle