class_docstr: Python class for ordered set.
  Code taken from https://github.com/buyalsky/ordered-hash-set/tree/5198b23e01faeac3f5398ab2c08cb013d14b3702.
code: def __iter__(self):
      self._iter = self._start
      return self
  
file_path: dowhy/dowhy/utils/ordered_set.py
label_desc: Use image node_id 9 for calling the OrderedSet obj's underlying member method code with example usage: obj.__iter__() and returns: self