docstr: Complete path stitching and download files.
  param chunk_size: Byte size of a single read, preferably an integer multiple of 2.
docstr_tok: ["Complete","path","stitching","and","download","files",".","param","chunk_size",":","Byte","size","of","a","single","read",",","preferably","an","integer","multiple","of","2","."]
code: def get_public_data(self, chunk_size=1024):
      """
      Complete path stitching and download files.
      param chunk_size: Byte size of a single read, preferably an integer multiple of 2.
      """
      invalidInputError(
          isinstance(chunk_size, int), "chunk_size must be int."
      )
      if not os.path.exists(self.dir_path):
          os.makedirs(self.dir_path)
  
      # check local file exists.
      if self.redownload:
          for val in self.url:
              download(val, self.dir_path, chunk_size)
      else:
          if not os.path.exists(self.final_file_path) and not set(
              DATASET_NAME[self.name]
          ).issubset(set(os.listdir(self.dir_path))):
              for val in self.url:
                  download(val, self.dir_path, chunk_size)
      return self
  
imports: import os
  import re
  import zipfile
  import tarfile
  import requests
  import logging
  import pandas
  import numpy
  from bigdl.chronos.data.tsdataset import TSDataset
  from bigdl.nano.utils.common import invalidInputError
label_desc: Use image node_id 2 for calling the PublicDataset obj's underlying member method code with example usage: obj.get_public_data(chunk_size) and returns: self