Appends the *item* to the end of the `Sequence`.

        :param item: any :class:`Structure`, :class:`Sequence`, :class:`Array`
            or :class:`Field` instance.

def append(self, item):
        """ Appends the *item* to the end of the `Sequence`.

        :param item: any :class:`Structure`, :class:`Sequence`, :class:`Array`
            or :class:`Field` instance.
        """
        if not is_any(item):
            raise MemberTypeError(self, item, member=len(self))
        self._data.append(item)