code: def out_of_bag_samples(self):
          
          #TODO:replace with more a generic pass-through wrapper?
          class O(object):
              def __init__(self, tree):
                  self.tree = tree
              def __len__(self):
                  return len(self.tree._out_of_bag_samples)
              def append(self, v):
                  self.tree._out_of_bag_mae_clean = False
                  return self.tree._out_of_bag_samples.append(v)
              def pop(self, v):
                  self.tree._out_of_bag_mae_clean = False
                  return self.tree._out_of_bag_samples.pop(v)
              def __iter__(self):
                  for _ in self.tree._out_of_bag_samples:
                      yield _
          return O(self)
docs: Returns the out-of-bag samples list, inside a wrapper to keep track
          of modifications.