code: def _normalize(
      df: DataFrame, num_cols: List, mean: Dict, std: Dict
  ) -> DataFrame:
      mean = Series(mean)
      std = Series(std)
      df[num_cols] = (df[num_cols] - mean) / std
      return df
  
file_path: lightning-flash/src/flash/tabular/classification/utils.py
imports: import logging
  from typing import Dict, List, Tuple
  import numpy
  from flash.core.utilities.imports import _PANDAS_AVAILABLE
label_desc: Use image node_id 3 for calling a global function with example usage: _normalize(df, num_cols, mean, std) and returns: df