class_docstr: Test case of invalid towhee command
docstr: target: test command 'lsS3' nonexistent path
  method: use lsS3 to list files with nonexistent path
  expected: get error message
code: def test_command_lsS3_nonexistent_path(self):
      """
      target: test command 'lsS3' nonexistent path
      method: use lsS3 to list files with nonexistent path
      expected: get error message
      """
      res = os.popen("towhee lsS3 -p abc/lpl").read()
      assert "not exist" in res
      return True
  
file_path: towhee/tests/testcases/test_command.py
imports: import os
  import sys
  import towhee
label_desc: Use image node_id 1 for calling the TestCommandInvalid obj's underlying member method code with example usage: obj.test_command_lsS3_nonexistent_path() and returns: True