code: def train_unsupervised(X_train, model=None):
      model = model if model is not None else ECOD()
      model.fit(X_train)
      return model
  
imports: from pyod.models.ecod import ECOD
  from pyod.models.xgbod import XGBOD
  from catboost import CatBoostClassifier
label_desc: Use image node_id 1 for calling a global function with example usage: train_unsupervised(X_train, model) and returns: model