Gets kind and possible names for :tl:`DocumentAttribute`.

def _get_kind_and_names(attributes):
        """Gets kind and possible names for :tl:`DocumentAttribute`."""
        kind = 'document'
        possible_names = []
        for attr in attributes:
            if isinstance(attr, types.DocumentAttributeFilename):
                possible_names.insert(0, attr.file_name)

            elif isinstance(attr, types.DocumentAttributeAudio):
                kind = 'audio'
                if attr.performer and attr.title:
                    possible_names.append('{} - {}'.format(
                        attr.performer, attr.title
                    ))
                elif attr.performer:
                    possible_names.append(attr.performer)
                elif attr.title:
                    possible_names.append(attr.title)
                elif attr.voice:
                    kind = 'voice'

        return kind, possible_names