code: def test_construction_invalid_readout_format(self):
      with self.assertRaises(TraitError):
          FloatSlider(readout_format="broken")
  
file_path: catboost/contrib/python/ipywidgets/py2/ipywidgets/widgets/tests/test_widget_float.py
imports: from unittest import TestCase
  from traitlets import TraitError
  from ipywidgets import FloatSlider
label_desc: Use image node_id 3 for calling the TestFloatSlider obj's underlying member method code with example usage: obj.test_construction_invalid_readout_format() without return types