code: def prepare_feature(self):
      for i, feature_info in enumerate(self.feature_infos, start=1):
          self.df, _, _ = feature_info.prepare(self.df)
          self.df = self.df.rename(columns={"x": f"x{i}"})
  
imports: from .info_plot_utils import TargetPlotEngine, PredictPlotEngine, InteractInfoPlotEngine
  from .utils import _make_list, _check_target, _q1, _q2, _q3, FeatureInfo, _check_dataset, _check_model, _calc_preds, _check_classes, _expand_params_for_interact
  import pandas
  from itertools import product
label_desc: Use image node_id 2 for calling the _InteractInfoPlot obj's underlying member method code with example usage: obj.prepare_feature() without return types