code: def get_num_trees(booster: xgb.Booster) -> int:
      data = [
          json.loads(d) for d in booster.get_dump(dump_format="json")
      ]
      return len(data)
  
imports: import json
  import pandas
  import pytest
  import xgboost
  from sklearn.datasets import load_breast_cancer
  from sklearn.model_selection import train_test_split
  import ray
  from ray import train, tune
  from ray.train import ScalingConfig
  from ray.train.constants import TRAIN_DATASET_KEY
  from ray.train.xgboost import XGBoostTrainer
label_desc: Use image node_id 3 for calling a global function with example usage: get_num_trees(booster) and returns: len