code: def create_v_function_for_env(env):
      assert isinstance(env.observation_space, gym.spaces.Box)
      ndim_obs = env.observation_space.low.size
      return v_function.FCVFunction(ndim_obs)
  
imports: from chainer import optimizers
  from chainer import testing
  import gym
  import gym.spaces
  import basetest_agents
  from chainerrl import agents
  from chainerrl import explorers
  from chainerrl import policies
  from chainerrl import q_functions
  from chainerrl import replay_buffer
  from chainerrl import v_function
label_desc: Use image node_id 5 for calling a global function with example usage: create_v_function_for_env(env) and returns: v_function