code: def _build_xgboost_operator_list():
      """
      List all supported XGBoost (Sklearn API) operators.
      """
      if xgboost_installed():
          from xgboost import XGBClassifier, XGBRanker, XGBRegressor
  
          return [XGBClassifier, XGBRanker, XGBRegressor]
  
      return []
  
file_path: hummingbird/hummingbird/ml/supported.py
imports: from collections import defaultdict
  from .exceptions import MissingConverter
  from ._utils import torch_installed, sklearn_installed, lightgbm_installed, xgboost_installed, onnx_runtime_installed, tvm_installed, sparkml_installed, prophet_installed
label_desc: Use image node_id 3 for calling a global function with example usage: _build_xgboost_operator_list() and returns: list, list