Cannot convert to bilby result object

I tried to convert a pesummary result object to a bilby result and got the following error:

In [23]: new_data = data.to_bilby()                                                                                                                                                                         
---------------------------------------------------------------------------
ModuleNotFoundError                       Traceback (most recent call last)
<ipython-input-23-f6c3bfd48aa1> in <module>
----> 1 new_data = data.to_bilby()

~/.conda/envs/bilby/lib/python3.7/site-packages/pesummary/gw/file/formats/pesummary.py in to_bilby(self)
    217         """
    218         from bilby.gw.result import CompactBinaryCoalescenceResult
--> 219         from bilby.core.priors import PriorDict, Uniform
    220         from pandas import DataFrame
    221 

ModuleNotFoundError: No module named 'bilby.core.priors'

I'm pretty sure this should be bilby.core.prior.