code: def test_sofm_neightbours_exceptions(self):
      with self.assertRaisesRegexp(ValueError, "Cannot find center"):
          sofm.find_neighbours_on_rect_grid(
              grid=np.zeros((3, 3)), center=(0, 0, 0), radius=1
          )
  
      with self.assertRaisesRegexp(ValueError, "Cannot find center"):
          sofm.find_step_scaler_on_rect_grid(
              grid=np.zeros((3, 3)), center=(0, 0, 0), std=1
          )
  
imports: import math
  import numpy
  from neupy import algorithms
  from neupy.exceptions import WeightInitializationError
  from neupy.algorithms.competitive import sofm
  from neupy.algorithms.competitive.neighbours import gaussian_df
  from base import BaseTestCase
label_desc: Use image node_id 1 for calling the SOFMNeigboursTestCase obj's underlying member method code with example usage: obj.test_sofm_neightbours_exceptions() without return types