bilby.result.read_in_result does not correctly import UniformComovingVolume prior

I read in a result using bilby.result.read_in_result. I would like to access the priors used to obtain this result. I would like to use the prior.prob function, but this fails due to the error:

AttributeError: 'str' object has no attribute 'prob'

When I print the type of each prior contained in my_result.priors, I get this:

<class 'bilby.core.prior.Uniform'>
Uniform(minimum=20, maximum=60, name='mass_1', latex_label='$m_1$', unit='$M_{\\odot}$', periodic_boundary=False)
<class 'bilby.core.prior.Uniform'>
Uniform(minimum=20, maximum=60, name='mass_2', latex_label='$m_2$', unit='$M_{\\odot}$', periodic_boundary=False)
<class 'str'>
UniformComovingVolume(minimum=500.0, maximum=3000.0, cosmology=FlatLambdaCDM(name="Planck15", H0=67.7 km / (Mpc s), Om0=0.307, Tcmb0=2.725 K, Neff=3.05, m_nu=[0.   0.   0.06] eV, Ob0=0.0486), name='luminosity_distance', latex_label='$d_L$', unit=Unit("Mpc"))
Traceback (most recent call last):
  File "prior_reweighting.py", line 45, in <module>
    prior_weights = result.get_weights_by_new_prior(new_prior)
  File "/anaconda3/lib/python3.7/site-packages/bilby-0.4.4-py3.7.egg/bilby/core/result.py", line 1198, in get_weights_by_new_prior
    w *= new_priors[prior_key].prob(val) / self.priors[prior_key].prob(val)
AttributeError: 'str' object has no attribute 'prob'

I suspect this is because UniformComovingVolume is a GW-specific prior, whilst Uniform is part of core, where read_in_result is defined.