Bug with Sound.spectrogram with low, high

[thesamovar]

One of many units bugs.

sound = whitenoise(100*ms, samplerate=16*kHz)
sound.spectrum(low=1*kHz, high=8000*kHz)

/home/lw1115/anaconda3/envs/python3/lib/python3.4/site-packages/brian2hears/sounds.py in spectrum(self, low, high, log_power, display)
    555             if high is None:
    556                 high = np.amax(freqs)*Hz
--> 557             I = np.logical_and(low <= freqs, freqs <= high)
    558             I2 = np.where(I)[0]
    559             Z = pxx[I2]

DimensionMismatchError: Cannot perform comparison 1. kHz <= [0.000e+00 1.000e+01 ... 1.598e+04 1.599e+04], units do not match (units are hertz and 1).