code: def preprocess_data(self, df, y_variable):
      # store y_var
      self.y_variable = y_variable
  
      # encode categorical var
      df = self.encode_categorical_var(df)
  
      # check and remove index column in the file.
      try:
          df = df.drop("index", axis=1)
      except:
          pass
  
      # finad and remove variables containing shap values
      self.df = self.remove_impact_columns(df)
  
      self.classification = self.is_classification()
  
      return True
  
file_path: explainx/lib/protodash.py
imports: from imports import *
  from encode_decode_cat_col import *
  from rescale_numeric_feature import *
  from PDASH import ProtodashExplainer
  from PDASH_utils import *
label_desc: Use image node_id 4 for calling the protodash obj's underlying member method code with example usage: obj.preprocess_data(df, y_variable) and returns: True