code: def test_CIELab_reconversion():
      color_list = [
          pg.Qt.QtGui.QColor("#100235")
      ]  # known problematic values
      for _ in range(20):
          qcol = pg.Qt.QtGui.QColor()
          qcol.setRgbF(*np.random.random((3)))
          color_list.append(qcol)
  
      for qcol1 in color_list:
          vec_Lab = pg.functions.colorCIELab(qcol1)
          qcol2 = pg.functions.CIELabColor(*vec_Lab)
          for val1, val2 in zip(qcol1.getRgb(), qcol2.getRgb()):
              assert (
                  abs(val1 - val2) <= 1
              ), f"Excess CIELab reconversion error ({qcol1.name() } > {vec_Lab } > {qcol2.name()})"
  
imports: from collections import OrderedDict
  from copy import deepcopy
  import numpy
  import pytest
  from numpy.testing import assert_array_almost_equal
  import pyqtgraph
  from pyqtgraph.functions import arrayToQPath, eq
  from pyqtgraph.Qt import QtGui
label_desc: Use image node_id 9 for calling a global function with example usage: test_CIELab_reconversion() without return types