code: def test_de_mutate_agent():
      new_de = de.DE()
  
      search_space = search.SearchSpace(
          n_agents=4,
          n_variables=2,
          lower_bound=[0, 0],
          upper_bound=[10, 10],
      )
  
      agent = new_de._mutate_agent(
          search_space.agents[0],
          search_space.agents[1],
          search_space.agents[2],
          search_space.agents[3],
      )
  
      assert agent.position[0][0] != 0
  
imports: import numpy
  from opytimizer.optimizers.evolutionary import de
  from opytimizer.spaces import search
label_desc: Use image node_id 3 for calling a global function with example usage: test_de_mutate_agent() without return types