How to use the eventkit.Op function in eventkit

return Tickfilter((2, 3, 67, 70), self)

    def bidasks(self) -> "Tickfilter":
        """
        Emit bid and ask ticks.
        """
        return Tickfilter((0, 1, 66, 69, 2, 3, 67, 70), self)

    def midpoints(self) -> "Tickfilter":
        """
        Emit midpoint ticks.
        """
        return Midpoints((), self)


class Tickfilter(Op):
    """
    Tick filtering event operators that ``emit(time, price, size)``.
    """
    __slots__ = ('_tickTypes',)

    def __init__(self, tickTypes, source=None):
        Op.__init__(self, source)
        self._tickTypes = set(tickTypes)

    def on_source(self, ticker):
        for t in ticker.ticks:
            if t.tickType in self._tickTypes:
                self.emit(t.time, t.price, t.size)

    def timebars(self, timer: Event) -> "TimeBars":
        """

def _on_timer(self, time):
        if self.bars:
            bar = self.bars[-1]
            if isNan(bar.close) and len(self.bars) > 1:
                bar.open = bar.high = bar.low = bar.close = \
                    self.bars[-2].close
            self.bars.updateEvent.emit(self.bars, True)
            self.emit(bar)
        self.bars.append(Bar(time))

    def _on_timer_done(self, timer):
        self._timer = None
        self.set_done()


class TickBars(Op):
    __slots__ = ('_count', 'bars')
    __doc__ = Tickfilter.tickbars.__doc__

    def __init__(self, count, source=None):
        Op.__init__(self, source)
        self._count = count
        self.bars: BarList = BarList()

    def on_source(self, time, price, size):
        if not self.bars or self.bars[-1].count == self._count:
            bar = Bar(time, price, price, price, price, size, 1)
            self.bars.append(bar)
        else:
            bar = self.bars[-1]
            bar.high = max(bar.high, price)
            bar.low = min(bar.low, price)

def _on_timer(self, time):
        if self.bars:
            bar = self.bars[-1]
            if isNan(bar.close) and len(self.bars) > 1:
                bar.open = bar.high = bar.low = bar.close = \
                    self.bars[-2].close
            self.bars.updateEvent.emit(self.bars, True)
            self.emit(bar)
        self.bars.append(Bar(time))

    def _on_timer_done(self, timer):
        self._timer = None
        self.set_done()


class TickBars(Op):
    __slots__ = ('_count', 'bars')
    __doc__ = Tickfilter.tickbars.__doc__

    def __init__(self, count, source=None):
        Op.__init__(self, source)
        self._count = count
        self.bars: BarList = BarList()

    def on_source(self, time, price, size):
        if not self.bars or self.bars[-1].count == self._count:
            bar = Bar(time, price, price, price, price, size, 1)
            self.bars.append(bar)
        else:
            bar = self.bars[-1]
            bar.high = max(bar.high, price)
            bar.low = min(bar.low, price)

return Tickfilter((2, 3, 67, 70), self)

    def bidasks(self) -> "Tickfilter":
        """
        Emit bid and ask ticks.
        """
        return Tickfilter((0, 1, 66, 69, 2, 3, 67, 70), self)

    def midpoints(self) -> "Tickfilter":
        """
        Emit midpoint ticks.
        """
        return Midpoints((), self)


class Tickfilter(Op):
    """
    Tick filtering event operators that ``emit(time, price, size)``.
    """
    __slots__ = ('_tickTypes',)

    def __init__(self, tickTypes, source=None):
        Op.__init__(self, source)
        self._tickTypes = set(tickTypes)

    def on_source(self, ticker):
        for t in ticker.ticks:
            if t.tickType in self._tickTypes:
                self.emit(t.time, t.price, t.size)

    def timebars(self, timer: Event) -> "TimeBars":
        """

class Bar(Object):
    defaults = dict(
        time=None,
        open=nan,
        high=nan,
        low=nan,
        close=nan,
        volume=0,
        count=0
    )
    __slots__ = defaults


class TimeBars(Op):
    __slots__ = ('_timer', 'bars',)
    __doc__ = Tickfilter.timebars.__doc__

    def __init__(self, timer, source=None):
        Op.__init__(self, source)
        self._timer = timer
        self._timer.connect(self._on_timer, None, self._on_timer_done)
        self.bars: BarList = BarList()

    def on_source(self, time, price, size):
        if not self.bars:
            return
        bar = self.bars[-1]
        if isNan(bar.open):
            bar.open = bar.high = bar.low = price
        bar.high = max(bar.high, price)

class Bar(Object):
    defaults = dict(
        time=None,
        open=nan,
        high=nan,
        low=nan,
        close=nan,
        volume=0,
        count=0
    )
    __slots__ = defaults


class TimeBars(Op):
    __slots__ = ('_timer', 'bars',)
    __doc__ = Tickfilter.timebars.__doc__

    def __init__(self, timer, source=None):
        Op.__init__(self, source)
        self._timer = timer
        self._timer.connect(self._on_timer, None, self._on_timer_done)
        self.bars: BarList = BarList()

    def on_source(self, time, price, size):
        if not self.bars:
            return
        bar = self.bars[-1]
        if isNan(bar.open):
            bar.open = bar.high = bar.low = price
        bar.high = max(bar.high, price)