code: def test_iwo_spatial_dispersal():
      new_iwo = iwo.IWO()
  
      new_iwo._spatial_dispersal(1, 10)
  
      assert new_iwo.sigma == 2.43019
  
file_path: opytimizer/tests/opytimizer/optimizers/evolutionary/test_iwo.py
imports: import numpy
  from opytimizer.optimizers.evolutionary import iwo
  from opytimizer.spaces import search
label_desc: Use image node_id 3 for calling a global function with example usage: test_iwo_spatial_dispersal() without return types