class FunctionGenerator:
    FUNCTION_SINE     = 0
    FUNCTION_SQUARE   = 1
    FUNCTION_SAWTOOTH = 2

    def __init__(self):
        raise Exception("This class should not be instantiated directly, please extend it instead")

    def setOn(self, channel: int) -> None:
        pass

    def setOff(self, channel: int) -> None:
        pass

    def setFrequency(self, channel: int, frequency: float) -> None:
        pass

    def setAmplitude(self, channel: int, amplitude: float) -> None:
        pass

    def setFunction(self, channel: int, function: int) -> None:
        pass