code: def __init__(self, start_mark=None, end_mark=None, encoding=None):
      self.start_mark = start_mark
      self.end_mark = end_mark
      self.encoding = encoding
  
label_desc: Use image node_id 1 to create a new StreamStartEvent object from inherited base classes: Event with example: obj = StreamStartEvent(start_mark, end_mark, encoding)