code: def test_endian_guess(self):
      # Check guesses of endian
      eh = self.header_class()
      assert eh.endianness == ">"
      assert self.header_class.guessed_endian(eh) == ">"
  
imports: import io
  import os
  import pathlib
  import numpy
  import pytest
  from numpy.testing import assert_almost_equal, assert_array_almost_equal, assert_array_equal
  from ...None import imageglobals
  from ...fileholders import FileHolder
  from ...openers import ImageOpener
  from ...spatialimages import HeaderDataError
  from ...testing import data_path
  from ...tests import test_spatialimages
  from ...tests import test_wrapstruct
  from ...tmpdirs import InTemporaryDirectory
  from ...volumeutils import sys_is_le
  from ...wrapstruct import WrapStructError
  from ..None import load, save
  from ..mghformat import MGHError, MGHHeader, MGHImage
label_desc: Use image node_id 6 for calling the TestMGHHeader obj's underlying member method code with example usage: obj.test_endian_guess() without return types