code: def _convert_types(self, filename: str, df: pd.DataFrame) -> None:
          
          if df.empty:
              return
  
          converters = self._config.nodes.get(filename, {}).get("converters", {})
          for col, converter in converters.items():
              if col in df.columns:
                  df[col] = converter(df[col])
docs: Apply type conversions