code: def return_to_base_policy(board, ship):
      shipyard_position = nearest_shipyard_position(board, ship)
  
      ship.next_action = head_to(
          board, ship.position, shipyard_position, ignore_teammates=True
      )
  
imports: import base64
  import pickle
  import random
  import numpy
  from zerosum_env.envs.halite.helpers import *
  from zerosum_env import make, evaluate
  from collections import deque
  import parl
  import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddle.distribution import Categorical
label_desc: Use image node_id 17 for calling a global function with example usage: return_to_base_policy(board, ship) without return types