code: def df_nybb(nybb_filename):
      df = read_file(nybb_filename)
      return df
  
imports: import os
  import warnings
  import pandas
  import geopandas
  from geopandas import GeoDataFrame, read_file, read_postgis
  import geopandas._compat
  from geopandas.io.sql import _get_conn, _write_postgis
  from geopandas.tests.util import create_postgis, create_spatialite, validate_boro_df
  import pytest
label_desc: Use image node_id 1 for calling a global function with example usage: df_nybb(nybb_filename) and returns: df