How to use the autopep8.FixPEP8 function in autopep8

def test_fix_e271_ignore_redundant(self):
        fix_pep8 = autopep8.FixPEP8(filename='',
                                    options=autopep8.parse_args(['']),
                                    contents='x = 1\n')

        self.assertEqual(
            [],
            fix_pep8.fix_e271({'line': 1,
                               'column': 2}))

def test_fix_e225_avoid_failure(self):
        fix_pep8 = autopep8.FixPEP8(filename='',
                                    options=autopep8.parse_args(['']),
                                    contents='    1\n')

        self.assertEqual(
            [],
            fix_pep8.fix_e225({'line': 1,
                               'column': 5}))

def test_fixpep8_class_constructor(self):
        line = 'print 1\nprint 2\n'
        with temporary_file_context(line) as filename:
            pep8obj = autopep8.FixPEP8(filename, None)
        self.assertEqual(''.join(pep8obj.source), line)

fixed_source = apply_global_fixes(tmp_source,
                                          options,
                                          filename=filename)

    passes = 0
    long_line_ignore_cache = set()
    while hash(fixed_source) not in previous_hashes:
        if options.pep8_passes >= 0 and passes > options.pep8_passes:
            break
        passes += 1

        previous_hashes.add(hash(fixed_source))

        tmp_source = copy.copy(fixed_source)

        fix = FixPEP8(
            filename,
            options,
            contents=tmp_source,
            long_line_ignore_cache=long_line_ignore_cache)

        fixed_source = fix.fix()

    sio = io.StringIO(fixed_source)
    return ''.join(normalize_line_endings(sio.readlines(), original_newline))

def supported_fixes():
    """Yield pep8 error codes that autopep8 fixes.

    Each item we yield is a tuple of the code followed by its
    description.

    """
    yield ('E101', docstring_summary(reindent.__doc__))

    instance = FixPEP8(filename=None, options=None, contents='')
    for attribute in dir(instance):
        code = re.match('fix_([ew][0-9][0-9][0-9])', attribute)
        if code:
            yield (
                code.group(1).upper(),
                re.sub(r'\s+', ' ',
                       docstring_summary(getattr(instance, attribute).__doc__))
            )

    for (code, function) in sorted(global_fixes()):
        yield (code.upper() + (4 - len(code)) * ' ',
               re.sub(r'\s+', ' ', docstring_summary(function.__doc__)))

    for code in sorted(CODE_TO_2TO3):
        yield (code.upper() + (4 - len(code)) * ' ',
               re.sub(r'\s+', ' ', docstring_summary(fix_2to3.__doc__)))