code: def init_default_multigrid_network(
      agent_type: str, agent_spec: specs.EnvironmentSpec
  ) -> ma_types.Networks:
      """Returns default networks for multigrid environment."""
      if agent_type == factories.DefaultSupportedAgent.PPO:
          return make_multigrid_ppo_networks(agent_spec)
      else:
          raise ValueError(f"Unsupported agent type: {agent_type}.")
  
file_path: acme/examples/multiagent/multigrid/helpers.py
imports: import functools
  from typing import Any, Dict, NamedTuple, Sequence
  from acme import specs
  from acme.agents.jax import ppo
  from acme.agents.jax.multiagent.decentralized import factories
  from acme.jax import networks
  from acme.jax import utils
  from acme.multiagent import types
  import haiku
  import jax
  import jax.numpy
  import numpy
  import tensorflow_probability
label_desc: Use image node_id 5 for calling a global function with example usage: init_default_multigrid_network(agent_type, agent_spec) and returns: make_multigrid_ppo_networks