code: def test_ssd_mean_global_solution():
      new_ssd = ssd.SSD()
  
      mean = new_ssd._mean_global_solution(1, 2, 3)
  
      assert mean != 0
  
file_path: opytimizer/tests/opytimizer/optimizers/social/test_ssd.py
imports: import numpy
  from opytimizer.optimizers.social import ssd
  from opytimizer.spaces import search
  from opytimizer.utils import constant
label_desc: Use image node_id 4 for calling a global function with example usage: test_ssd_mean_global_solution() without return types