code: def place_coin(red_pos_i, blue_pos_i, grid_size):
      red_pos_flat = _flatten_index(red_pos_i, grid_size)
      blue_pos_flat = _flatten_index(blue_pos_i, grid_size)
      possible_coin_pos = np.array(
          [
              x
              for x in range(9)
              if ((x != blue_pos_flat) and (x != red_pos_flat))
          ]
      )
      flat_coin_pos = np.random.choice(possible_coin_pos)
      return _unflatten_index(flat_coin_pos, grid_size)
  
imports: import copy
  from collections import Iterable
  import numpy
  from numba import jit, prange
  from numba.typed import List
  from ray.rllib.examples.env.coin_game_non_vectorized_env import CoinGame
  from ray.rllib.utils import override
label_desc: Use image node_id 7 for calling a global function with example usage: place_coin(red_pos_i, blue_pos_i, grid_size) and returns: _unflatten_index