TypeError in signals.py

[prjemian]

~/.ipython/profile_bluesky/startup/20-detectors.py in <module>
     49     eta=0.3 + 0.5*np.random.uniform(),
     50     sigma=0.001 + 0.05*np.random.uniform(),
---> 51     scale=1e5)

~/.conda/envs/bluesky/lib/python3.6/site-packages/apstools/signals.py in __init__(self, name, motor, motor_field, center, eta, scale, sigma, bkg, noise, noise_multiplier, **kwargs)
    136             return v
    137
--> 138         ophyd.sim.SynSignal.__init__(name=name, func=pvoigt, **kwargs)

TypeError: __init__() missing 1 required positional argument: 'self'