code: def test_read_series():
      img = ci.Cifti2Image.from_filename(DATA_FILE4)
      series_mapping = img.header.matrix.get_index_map(0)
      assert series_mapping.series_start == 0.0
      assert series_mapping.series_step == 1.0
      assert series_mapping.series_unit == "SECOND"
      assert series_mapping.series_exponent == 0.0
      assert series_mapping.number_of_series_points == img.shape[0]
  
imports: import io
  from os.path import dirname
  from os.path import join
  import numpy
  import pytest
  from numpy.testing import assert_array_almost_equal
  from packaging.version import Version
  import nibabel
  from nibabel import cifti2
  from nibabel.cifti2.parse_cifti2 import _Cifti2AsNiftiHeader
  from nibabel.tests import test_nifti2
  from nibabel.tests.nibabel_data import get_nibabel_data, needs_nibabel_data
  from nibabel.tmpdirs import InTemporaryDirectory
label_desc: Use image node_id 12 for calling a global function with example usage: test_read_series() without return types