code: def df_linear_ring():
      from shapely.geometry import LinearRing
  
      df = geopandas.GeoDataFrame(
          {"geometry": [LinearRing(((0, 0), (0, 1), (1, 1), (1, 0)))]},
          crs="epsg:4326",
      )
      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 8 for calling a global function with example usage: df_linear_ring() and returns: df