code: def test_osgb(self, approx):
      self._check_osgb(ccrs.OSGB(approx=approx))
  
imports: import copy
  from io import BytesIO
  import os
  from pathlib import Path
  import pickle
  import warnings
  import numpy
  from numpy.testing import assert_almost_equal, assert_array_equal
  from numpy.testing import assert_array_almost_equal
  import pyproj
  import pytest
  import shapely.geometry
  import cartopy.crs
label_desc: Use image node_id 4 for calling the TestCRS obj's underlying member method code with example usage: obj.test_osgb(approx) without return types