code: def initialize_grid(world_size, inner):
      
      data = []
  
      for i in range(world_size[1]):
          data.append([])
          for j in range(world_size[0]):
              data[i].append(deepcopy(inner))
      return data
docs: Creates an empty grid (2d list) with the dimensions specified in
      world_size. Each element is initialized to the inner argument.