class_docstr: USPS Dataset.
  
  Args:
      root (string): Root directory of dataset where dataset file exist.
      train (bool, optional): If True, resample from dataset randomly.
      download (bool, optional): If true, downloads the dataset
          from the internet and puts it in root directory.
          If dataset is already downloaded, it is not downloaded again.
      transform (callable, optional): A function/transform that takes in
          an PIL image and returns a transformed version.
          E.g, ``transforms.RandomCrop``
docstr: Download dataset.
docstr_tok: ["Download","dataset","."]
code: def download(self):
      """Download dataset."""
      filename = os.path.join(self.root, self.filename)
      dirname = os.path.dirname(filename)
      if not os.path.isdir(dirname):
          os.makedirs(dirname)
      if os.path.isfile(filename):
          return
      logging.info(
          f"Download {self.url} to {os.path.abspath(filename)}"
      )
      urllib.request.urlretrieve(self.url, filename)
      logging.info("[DONE]")
      return
  
file_path: pykale/kale/loaddata/usps.py
imports: import gzip
  import logging
  import os
  import pickle
  import urllib
  import numpy
  import torch
  import torch.utils.data
label_desc: Use image node_id 5 for calling the USPS obj's underlying member method code with example usage: obj.download() without return types