<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_default_section(self, file_name):
 """Returns first non-DEFAULT section; falls back to DEFAULT."""

        if not os.path.isfile(file_name):
            return 'DEFAULT'
        parser = self.make_parser()
        with open(file_name) as fp:
            parser.read_file(fp)
        sections = parser.sections()
        section = sections[0] if len(sections) > 0 else 'DEFAULT'
        return section