return the path for a file we can use to back up the table

def _get_outfile_path(self, table):
        """return the path for a file we can use to back up the table"""
        self.outfile_count += 1
        outfile = os.path.join(self.directory, '{:03d}_{}.sql.gz'.format(self.outfile_count, table))
        return outfile