def test_singlePartExtended(self):
        """
        L{imap4.getBodyStructure} returns a list giving the basic and extended
        fields for a I{BODYSTRUCTURE} response if passed C{True} for the
        C{extended} parameter.
        """
        body = b'hello, world'
        major = 'image'
        minor = 'jpeg'
        charset = 'us-ascii'
        identifier = 'some kind of id'
        description = 'great justice'
        encoding = 'maximum'
        md5 = 'abcdefabcdef'
        msg = FakeyMessage({
                'content-type': major + '/' + minor +
                                 '; charset=' + charset + '; x=y',
                'content-id': identifier,
                'content-description': description,
                'content-transfer-encoding': encoding,
                'content-md5': md5,
                'content-disposition': 'attachment; name=foo; size=bar',
                'content-language': 'fr',
                'content-location': 'France',
                }, (), '', body, 123, None)
        structure = imap4.getBodyStructure(msg, extended=True)
        self.assertEqual(
            [major, minor, ["charset", charset, 'x', 'y'], identifier,
             description, encoding, len(body), md5,
             ['attachment', ['name', 'foo', 'size', 'bar']], 'fr', 'France'],
            structure)

        L{imap4.getBodyStructure} returns a list giving the basic and extended
        fields for a I{BODYSTRUCTURE} response if passed C{True} for the
        C{extended} parameter.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/mail/test/test_imap.py