code: def test_centroid_x(self):
      self.assertEqual(self.xc, (self.left + self.right) / 2.0)
  
imports: import unittest
  from holoviews.core import AARectangle, BoundingBox
label_desc: Use image node_id 7 for calling the TestBoundingBox obj's underlying member method code with example usage: obj.test_centroid_x() without return types