code: def test_invalid_travel_mode(self):
      with self.assertRaises(traitlets.TraitError):
          Directions(self.start, self.end, travel_mode="wrong")
  
imports: import unittest
  import pytest
  import traitlets
  from ..directions import Directions, DEFAULT_STROKE_COLOR
label_desc: Use image node_id 14 for calling the DirectionsLayer obj's underlying member method code with example usage: obj.test_invalid_travel_mode() without return types