code: def preprocess_df(df, stores_df):
      df = preprocess_dates(df)
      df = preprocess_stores(df, stores_df)
  
      for column in int_columns:
          df[column] = pd.to_numeric(
              df[column].fillna(0), downcast="integer"
          )
  
      df["StateHoliday"] = df["StateHoliday"].astype(str)
      df.loc[df["StateHoliday"] == "0", "StateHoliday"] = "No"
  
      return df
  
file_path: ludwig/ludwig/datasets/loaders/rossman_store_sales.py
imports: import calendar
  import os
  from typing import List
  import numpy
  import pandas
  from ludwig.datasets.loaders.dataset_loader import DatasetLoader
label_desc: Use image node_id 3 for calling a global function with example usage: preprocess_df(df, stores_df) and returns: df