code: def test_space_best_agent_setter():
      new_space = space.Space()
  
      try:
          new_space.best_agent = None
      except:
          new_space.best_agent = agent.Agent(1, 1, 0, 1)
  
      assert isinstance(new_space.best_agent, agent.Agent)
  
imports: import numpy
  import pytest
  from opytimizer.core import agent, space
label_desc: Use image node_id 10 for calling a global function with example usage: test_space_best_agent_setter() without return types