code: def ks_synth(freq):
    
    ks_mem = (sum(lz.sinusoid(x * freq) for x in [1, 3, 9]) +
              lz.white_noise() + lz.Stream(-1, 1)) / 5
    return lz.karplus_strong(freq, memory=ks_mem)
docs: Synthesize the given frequency into a Stream by using a model based on
    Karplus-Strong.