During the algorithm initialization, the following exception has occurred: cannot instantiate abstract class
  at ConfigureIndicators
    self.pivot_highs[symbol] = PivotHighIndicator(f"PivotHigh_{symbol}", 7, 7)
                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 in main.py: line 154
  at Initialize
    self.ConfigureIndicators()
 in main.py: line 128
 cannot instantiate abstract class

Can you please help me to resolve this issue?

class PivotHighIndicator(IndicatorBase[TradeBar]):

    def __init__(self, name, left_bars, right_bars):

        super().__init__(name)

        self.left_bars = left_bars

        self.right_bars = right_bars

        self.values = deque(maxlen=left_bars + right_bars + 1)

        self._warm_up_period = left_bars + right_bars + 1

        self._current = IndicatorDataPoint()

class PivotLowIndicator(IndicatorBase[TradeBar]):

    def __init__(self, name, left_bars, right_bars):

        super().__init__(name)

        self.left_bars = left_bars

        self.right_bars = right_bars

        self.values = deque(maxlen=left_bars + right_bars + 1)

        self._warm_up_period = left_bars + right_bars + 1

        self._current = IndicatorDataPoint()

Please help me to resolve this issue? Really appreciate your feedback.