How to use the essentia.standard.NoiseAdder function in essentia

def scratch(audio, coordinate = False):
    """ 
    This function performs scratching effects to sound arrays 
    :param audio: the signal you want to scratch
    :param coordinate: to set this to True, a decision variable must be given (a distance) to use a velocity given a learned distance
    :returns:                                                                                                         
      - scratched signal
    """
    proportion = range(len(audio))[0:len(audio):len(audio)/16]
    prop = overlapped_intervals(proportion)
    audio = NoiseAdder(level = -100)(audio) #create noisy part for vinyl in turntable 
    audio = LowPass(cutoffFrequency = 22050)(audio)
    audio = LowPass(cutoffFrequency = 30)(audio)
    def hand_move(audio, rev_audio, prop, slices): #simulation of hand motion in a turntable
        if (coordinate == False) or (coordinate == None):               
            forwards = np.concatenate([speedx(audio[i[0]:i[1]], randint(2,3)) for i in prop])          
            backwards = np.concatenate([speedx(rev_audio[i[0]:i[1]], randint(2,3)) for i in prop])    
        else:
            factor = distance_velocity(audio, coordinate)
            forwards = np.concatenate([speedx(audio[i[0]:i[1]], factor) for i in prop]) 
            backwards = np.concatenate([speedx(audio[i[0]:i[1]], factor) for i in prop])                        
        cf = crossfade(forwards, backwards, slices)
        return cf
    rev_audio = audio[::-1]
    hand_a = lambda: hand_move(audio, rev_audio, prop, slices = [prop, prop])
    hand_b = lambda: hand_move(audio, rev_audio, prop, slices = [prop[:12], prop[:12]])
    hand_c = lambda: hand_move(audio, rev_audio, prop, slices = [prop[1:], prop])