Py3.6 issue in .residuals call

[fraserw]

After doing a successful orb= mp_ephem.BKOrbit(observations) call, orb.residuals causes the following traceback. Same code in python 2.7 doesn't error out.

Can provide source code if helpful.

Traceback (most recent call last):
File "orbfit_blinks.py", line 71, in
print(orb.residuals)
File "/home/fraserw/anaconda3/lib/python3.6/site-packages/mp_ephem/bk_orbit.py", line 317, in residuals
self.compute_residuals()
File "/home/fraserw/anaconda3/lib/python3.6/site-packages/mp_ephem/bk_orbit.py", line 298, in compute_residuals
self.predict(observation.date, obs_code=int(observation.observatory_code))
File "/home/fraserw/anaconda3/lib/python3.6/site-packages/mp_ephem/bk_orbit.py", line 493, in predict
self._date = str(_date)
File "/home/fraserw/anaconda3/lib/python3.6/site-packages/astropy/time/core.py", line 445, in str
return str(getattr(self, self.format))
File "/home/fraserw/anaconda3/lib/python3.6/site-packages/astropy/time/core.py", line 1131, in getattr
value = tm._shaped_like_input(tm._time.to_value(parent=tm))
File "/home/fraserw/anaconda3/lib/python3.6/site-packages/astropy/time/formats.py", line 214, in to_value
return self.value
File "/home/fraserw/anaconda3/lib/python3.6/site-packages/astropy/time/formats.py", line 808, in value
for kwargs in self.str_kwargs():
File "/home/fraserw/anaconda3/lib/python3.6/site-packages/mp_ephem/time_mpc.py", line 113, in str_kwargs
self.jd1, self.jd2_filled)
AttributeError: 'TimeMPC' object has no attribute 'jd2_filled'