code: def write_predictions(self, df: pd.DataFrame, path: str):
      df, column_shapes = flatten_df(df, self)
      self.to_parquet(df, path)
      save_json(
          os.path.join(
              os.path.dirname(path), PREDICTIONS_SHAPES_FILE_NAME
          ),
          column_shapes,
      )
  
imports: import os
  import numpy
  import pandas
  from ludwig.data.dataframe.base import DataFrameEngine
  from ludwig.globals import PREDICTIONS_SHAPES_FILE_NAME
  from ludwig.utils.data_utils import load_json, save_json, split_by_slices
  from ludwig.utils.dataframe_utils import flatten_df, unflatten_df
label_desc: Use image node_id 16 for calling the PandasEngine obj's underlying member method code with example usage: obj.write_predictions(df, path) without return types