Using `None` for kwargs in `init` causes error

Choosing not to specify all or some kwargs when initializing a PopulationResult object,

from popsummary.popresult import PopulationResult

result = PopulationResult('test.h5')

produces the error:

File ~/anaconda3/envs/gwinferno/lib/python3.10/site-packages/popsummary/popresult.py:55, in PopulationResult.__init__(self, fname, hyperparameters, hyperparameter_descriptions, hyperparameter_latex_labels, references, model_names, events, event_waveforms, event_sample_IDs, event_parameters)
     53 f.create_group('posterior')
     54 f.create_group('prior')
---> 55 f.attrs['events'] = events
     56 f.attrs['event_waveforms'] = event_waveforms
     57 f.attrs['event_sample_IDs'] = event_sample_IDs

File h5py/_objects.pyx:54, in h5py._objects.with_phil.wrapper()

File h5py/_objects.pyx:55, in h5py._objects.with_phil.wrapper()

File ~/anaconda3/envs/gwinferno/lib/python3.10/site-packages/h5py/_hl/attrs.py:104, in AttributeManager.__setitem__(self, name, value)
     96 @with_phil
     97 def __setitem__(self, name, value):
     98     """ Set a new attribute, overwriting any existing attribute.
     99 
    100     The type and shape of the attribute are determined from the data.  To
    101     use a specific type or shape, or to preserve the type of an attribute,
    102     use the methods create() and modify().
    103     """
...
File h5py/h5t.pyx:1688, in h5py.h5t.py_create()

File h5py/h5t.pyx:1748, in h5py.h5t.py_create()

TypeError: Object dtype dtype('O') has no native HDF5 equivalent

A possible fix could be to replace the default of these kwargs (None) with [] and any if statements like if x is None with if not x. You would also have to replace any if overwrite statements with if overwrite and not x, i.e. if overwrite is true and if x is not an empty list, then overwrite the data.

Using `None` for kwargs in `__init__` causes error

Using `None` for kwargs in `init` causes error