def __init__(self, tree):
        """
        Initialise the data structure, compute m and M.
        """
        info = self._precompute(tree._tree)
        m, M = self._get_vectors(tree._tree, info)
        self.little_m = m
        self.big_m = M
        self.tree = tree
def __init__ ( self , tree ) : info = self . _precompute ( tree . _tree ) m , M = self . _get_vectors ( tree . _tree , info ) self . little_m = m self . big_m = M self . tree = tree
Initialise the data structure, compute m and M.