code: def testCenter(self):
      layout = Layout([(-2, 0), (-2, -2), (0, -2), (0, 0)])
      layout.center()
      self.assertEqual(
          layout.coords, [[-1, 1], [-1, -1], [1, -1], [1, 1]]
      )
      layout.center(5, 5)
      self.assertEqual(layout.coords, [[4, 6], [4, 4], [6, 4], [6, 6]])
      self.assertRaises(ValueError, layout.center, 3)
      self.assertRaises(TypeError, layout.center, p=6)
  
imports: import unittest
  from math import hypot
  from igraph import Graph, Layout, BoundingBox, InternalError
  from igraph import umap_compute_weights
label_desc: Use image node_id 8 for calling the LayoutTests obj's underlying member method code with example usage: obj.testCenter() without return types