code: def test_mghheader_default_structarr():
      hdr = MGHHeader.default_structarr()
      assert hdr["version"] == 1
      assert_array_equal(hdr["dims"], 1)
      assert hdr["type"] == 3
      assert hdr["dof"] == 0
      assert hdr["goodRASFlag"] == 1
      assert_array_equal(hdr["delta"], 1)
      assert_array_equal(
          hdr["Mdc"], [[-1, 0, 0], [0, 0, 1], [0, -1, 0]]
      )
      assert_array_equal(hdr["Pxyz_c"], 0)
      assert hdr["tr"] == 0
      assert hdr["flip_angle"] == 0
      assert hdr["te"] == 0
      assert hdr["ti"] == 0
      assert hdr["fov"] == 0
  
      for endianness in (None,) + BIG_CODES:
          hdr2 = MGHHeader.default_structarr(endianness=endianness)
          assert hdr2 == hdr
          assert hdr2.view(hdr2.dtype.newbyteorder(">")) == hdr
  
      for endianness in LITTLE_CODES:
          with pytest.raises(ValueError):
              MGHHeader.default_structarr(endianness=endianness)
  
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 16 for calling a global function with example usage: test_mghheader_default_structarr() without return types