code: def test_read_postgis_custom_geom_col(
      self, connection_postgis, df_nybb
  ):
      con = connection_postgis
      geom_col = "the_geom"
      create_postgis(con, df_nybb, geom_col=geom_col)
  
      sql = "SELECT * FROM nybb;"
      df = read_postgis(sql, con, geom_col=geom_col)
  
      validate_boro_df(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 3 for calling the TestIO obj's underlying member method code with example usage: obj.test_read_postgis_custom_geom_col(connection_postgis, df_nybb) without return types