def join(self, other):
        r"""
        Args:
            other (?):

        CommandLine:
            python -m sortedcontainers.sortedlist join2

        Example:
            >>> from utool.experimental.dynamic_connectivity import *  # NOQA
            >>> self = EulerTourList([1, 2, 3, 2, 4, 2, 1], load=3)
            >>> other = EulerTourList([0, 5, 9, 5, 0], load=3)
            >>> result = self.join(other)
            >>> print(result)
        """
        assert self._load == other._load, 'loads must be the same'
        self._lists.extend(other._lists)
        self._cumlen.extend([c + self._len for c in other._cumlen])
        self._len += other._len