code: def test_subheader_size(self):
      assert self.subhdr_class._subhdrdtype.itemsize == 510
  
imports: import os
  import warnings
  from pathlib import Path
  from unittest import TestCase
  import numpy
  import pytest
  from numpy.testing import assert_array_almost_equal, assert_array_equal
  from ..ecat import EcatHeader, EcatImage, EcatSubHeader, get_frame_order, get_series_framenumbers, read_mlist
  from ..openers import Opener
  from ..testing import data_path, suppress_warnings
  from ..tmpdirs import InTemporaryDirectory
  from .None import test_wrapstruct
  from .test_fileslice import slicer_samples
label_desc: Use image node_id 1 for calling the TestEcatSubHeader obj's underlying member method code with example usage: obj.test_subheader_size() without return types