code: def model_fitted(self):
      return self.num_boosted_rounds != 0
  
file_path: ivy/ivy/functional/frontends/xgboost/gbm/gbm.py
imports: import ivy
  from ivy.functional.frontends.xgboost.objective.regression_loss import LogisticRegression
  from ivy.functional.frontends.xgboost.linear.updater_coordinate import coordinate_updater
  from copy import deepcopy
label_desc: Use image node_id 3 for calling the GBLinear obj's underlying member method code with example usage: obj.model_fitted() and returns: unknown