class_docstr: Test download tools
code: def test_error(self):
      try:
          os.makedirs(self.target_file, exist_ok=True)
          download_from_url(self.url, "./")
      except RuntimeError:
          os.removedirs(self.target_file)
      try:
          download_from_url(self.url, "./", hash_prefix="xxx")
      except AssertionError:
          checksum(self.target_file, "7222f2e")
  
      download_from_url(self.url, "./", hash_prefix="7222f2e")
      self.assertTrue(os.path.isfile(self.target_file))
  
file_path: towhee/tests/unittests/models/utils/test_download.py
imports: import unittest
  import os
  from towhee.models.utils.download import download_from_url, checksum
label_desc: Use image node_id 4 for calling the TestDownload obj's underlying member method code with example usage: obj.test_error() without return types