Let exception fire or return None

[Cecil Westerhof]

I have a function to fetch a message from a file:
    def get_indexed_message(message_filename, index):
        """
        Get index message from a file, where 0 gets the first message
        """

        return open(expanduser(message_filename), 'r').readlines()[index].rstrip()

What is more the Python way: let the exception fire like this code
when index is to big, or catching it and returning None?

I suppose working zero based is OK.

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof