code: def check_prepare_results(self, df, count_df, summary_df):
      assert "x" in df.columns
      assert set(count_df.columns) == set(["x", "count", "count_norm"])
      summary_cols = ["x", "value", "count"]
      assert (
          set(summary_cols)
          <= set(summary_df.columns)
          <= set(summary_cols + ["percentile"])
      )
  
imports: import pandas
  import numpy
  import pytest
  from pdpbox.utils import FeatureInfo, _to_rgba, _check_col, _check_dataset, _make_list, _check_model, _check_classes, _check_memory_limit, _check_frac_to_plot, _calc_n_jobs, _get_string, _expand_params_for_interact, _calc_preds, _check_cluster_params, _check_plot_engine, _check_pdp_interact_plot_type
label_desc: Use image node_id 9 for calling the TestFeatureInfo obj's underlying member method code with example usage: obj.check_prepare_results(df, count_df, summary_df) without return types