def METHOD_NAME(self):
    for fname in self._get_paths():
        with open(fname) as f:
            longer = []
            for i, line in enumerate(f):
                if len(line) > 80:
                    longer.append('line [%d] %s' % (i + 1, line))
            if len(longer) > 0:
                raise AssertionError('Lines longer than 80\n%s'
                                     % '\n'.join(longer))