code: def set_leaf(self) -> None:
      self.expand(None, [])
  
imports: from dataclasses import dataclass
  import decimal
  from typing import Any
  from typing import Dict
  from typing import Iterable
  from typing import List
  from typing import Optional
  from typing import Sequence
  from typing import Tuple
  import numpy
  from optuna._experimental import experimental_class
  from optuna.distributions import BaseDistribution
  from optuna.distributions import CategoricalDistribution
  from optuna.distributions import FloatDistribution
  from optuna.distributions import IntDistribution
  from optuna.samplers import BaseSampler
  from optuna.samplers._lazy_random_state import LazyRandomState
  from optuna.study import Study
  from optuna.trial import create_trial
  from optuna.trial import FrozenTrial
  from optuna.trial import TrialState
label_desc: Use image node_id 2 for calling the _TreeNode obj's underlying member method code with example usage: obj.set_leaf() without return types