code: def to(self, device: torch.device, dtype: torch.dtype) -> "_PriorBox":
      self.device = device
      self.dtype = dtype
      return self
  
imports: import math
  from enum import Enum
  from typing import Dict, List, Optional, Tuple
  import torch
  import torch.nn.functional
  from torch import nn
  from kornia.geometry.bbox import nms
  from kornia.utils.helpers import map_location_to_cpu
label_desc: Use image node_id 2 for calling the _PriorBox obj's underlying member method code with example usage: obj.to(device, dtype) and returns: self