class_docstr: A class to track record of every temporary files created by the tests.
code: def tmp_folder(cls, name=""):
      cls.tmp_folders.add(name)
      return name
  
imports: import shutil
  import os
label_desc: Use image node_id 2 for calling the TmpFileManager obj's underlying member method code with example usage: obj.tmp_folder(cls, name) and returns: name