code: def _prepare_calculate(self):
      self.n_classes, self.pred_func, self.from_model = _check_model(
          self.model, self.n_classes, self.pred_func
      )
      self.target = (
          list(np.arange(self.n_classes)) if self.n_classes > 2 else [0]
      )
  
imports: from .pdp_utils import PDPIsolatePlotEngine, PDPInteractPlotEngine
  from .utils import _check_frac_to_plot, _make_list, _check_classes, _calc_n_jobs, FeatureInfo, _check_model, _calc_preds, _expand_params_for_interact, _check_dataset, _check_cluster_params, _check_plot_engine, _check_pdp_interact_plot_type
  import pandas
  import numpy
  from pqdm.processes import pqdm
  from tqdm.auto import tqdm
  import warnings
label_desc: Use image node_id 2 for calling the _PDPBase obj's underlying member method code with example usage: obj._prepare_calculate() without return types