code: def bfs(node: Node) -> types.Action:
      """Breadth-first search policy."""
      visit_counts = np.array(
          [c.visit_count for c in node.children.values()]
      )
      return argmax(-visit_counts)
  
file_path: acme/acme/agents/tf/mcts/search.py
imports: import dataclasses
  from typing import Callable, Dict
  from acme.agents.tf.mcts import models
  from acme.agents.tf.mcts import types
  import numpy
label_desc: Use image node_id 2 for calling a global function with example usage: bfs(node) and returns: argmax