code: def test_empty(self):
      super().test_empty()
      hdr = self.header_class()
      assert hdr["scl_slope"] == 1
  
imports: import itertools
  import unittest
  from io import BytesIO
  import numpy
  import pytest
  from numpy.testing import assert_array_almost_equal, assert_array_equal
  from ..optpkg import optional_package
  from ..casting import sctypes_aliases, shared_range, type_info
  from ..spatialimages import HeaderDataError
  from ..spm99analyze import HeaderTypeError, Spm99AnalyzeHeader, Spm99AnalyzeImage
  from ..testing import assert_allclose_safely, bytesio_filemap, bytesio_round_trip, suppress_warnings
  from ..volumeutils import _dt_min_max, apply_read_scaling
  from .None import test_analyze
label_desc: Use image node_id 1 for calling the TestSpm99AnalyzeHeader obj's underlying member method code with example usage: obj.test_empty() without return types