code: def _init_trees(self, n_features: int):
      for _ in range(self.n_models):
          self.data.append(
              self._new_member(
                  max_features=self._calculate_max_features(n_features),
                  max_depth=self._calculate_tree_depth(),
                  seed=self._rng.randint(
                      0, sys.maxsize
                  ),  # randomly creates a new seed
              )
          )
          self._perfs.append(self.track_metric.clone())
  
imports: from __future__ import annotations
  import abc
  import collections
  import math
  import random
  import sys
  from river import base, drift, metrics, tree, utils
  from river.tree.nodes.et_nodes import ETLeafAdaptive, ETLeafMean, ETLeafModel
  from river.tree.splitter.random_splitter import RegRandomSplitter
label_desc: Use image node_id 6 for calling the ExtraTrees obj's underlying member method code with example usage: obj._init_trees(n_features) without return types