def __init__(self):
    super().__init__()
    self._count = None
    self._first = None
    self._last = None
    self.reset()
    self.add_to_head()
def __init__(self):
    super().__init__()
    self._count = None
    self._first = None
    self._last = None
    self.reset()
    self.add_to_head()