def _delete_node_with_one_child(self, M):
C = M.l or M.r
assert(M.color is BLACK)
if C.color is RED:
C.color = BLACK
BinarySearchTree._delete_node_with_one_child(self, M)
def _delete_node_with_one_child(self, n):
par = n.parent
BinarySearchTree._delete_node_with_one_child(self, n)
self._rebalance_till_root(par)
