How to use the changelog.Changelog function in changelog

def test_add_changelog_section(self):
        f = open('test_modify_changelog2')
        c = f.read()
        f.close()
        cl = changelog.Changelog(c)
        cl.new_block(package='gnutls14',
                version=changelog.Version('1:1.4.1-3'),
                distributions='experimental',
                urgency='low',
                author='James Westby ')

        self.assertRaises(changelog.ChangelogCreateError, cl.__str__)

        cl.set_date('Sat, 16 Jul 2008 11:11:08 +0200')
        cl.add_change('')
        cl.add_change('  * Foo did not work, let us try bar')
        cl.add_change('')

        f = open('test_modify_changelog3')
        c = f.read()
        f.close()

def test_magic_version_properties(self):
        f = open('test_changelog')
        c = changelog.Changelog(f)
        f.close()
        self.assertEqual(c.debian_version, '1')
        self.assertEqual(c.full_version, '1:1.4.1-1')
        self.assertEqual(c.upstream_version, '1.4.1')
        self.assertEqual(c.epoch, '1')
        self.assertEqual(str(c.version), c.full_version)

def test_set_version_with_string(self):
        f = open('test_modify_changelog1')
        c1 = changelog.Changelog(f.read())
        f.seek(0)
        c2 = changelog.Changelog(f.read())
        f.close()
        c1.version = '1:2.3.5-2'
        c2.version = changelog.Version('1:2.3.5-2')
        self.assertEqual(c1.version, c2.version)
        self.assertEqual((c1.full_version, c1.epoch, c1.upstream_version,
                          c1.debian_version),
                         (c2.full_version, c2.epoch, c2.upstream_version,
                          c2.debian_version))

def test_unicode_object_input(self):
        f = open('test_changelog_unicode')
        c_str = f.read()
        f.close()
        c_unicode = c_str.decode('utf-8')
        c = changelog.Changelog(c_unicode)
        self.assertEqual(unicode(c), c_unicode)
        self.assertEqual(str(c), c_str)

def __init__(self, name, part, directory):
        self.name = name
        self.part = part
        if not self.part:
            raise Exception('Part required')
        self.directory = directory
        self.git_repo = git.Repo(self.directory)
        self._bumped = False

        self.current_version = self._get_current_version()
        self.new_version = self._get_new_version()
        self._changelog = changelog.Changelog(os.path.join(self.directory, 'CHANGELOG.md'))

def ast_to_changelog(node):
    changelog = None
    headings = ast_to_headings(node)

    if len(headings) > 0 and headings[0].level == 1:
        changelog = Changelog(headings[0].title)
        headings = headings[1:]
    else:
        raise Exception('Changelog does not start with a level 1 heading, including the changelog name.')

    if any(map(lambda h: h.level == 1, headings)):
        raise Exception('Changelog has multiple level 1 headings.')

    release = None

    for heading in headings:
        if heading.level == 2:
            if release:
                changelog.releases.append(release)

            release = Release(heading.title)
        elif heading.level == 3:

def __init__(self, name, part, directory):
        self.name = name
        self.part = part
        if not self.part:
            raise Exception('Part required')
        self.directory = directory
        self.git_repo = git.Repo(self.directory)
        self._bumped = False

        self.current_version = self._get_current_version()
        self.new_version = self._get_new_version()
        self._changelog = changelog.Changelog(os.path.join(self.directory, 'CHANGELOG.md'))

def change(self):
		self.session.open(Changelog, Version)