parameter_sweep crashes when sweeping over only one parameter

[seanpolyn]

I was trying to just sweep over B_rec, but it kept crashing. Then I added B_enc to the param_names and it worked. It may be easiest to replicate by taking the plot_sweep_B code and removing B_enc from the param_names. I don't want to upload my scratch script into the cymr project, and it won't let me attach a py file here.

Here's the error output when there's just one param being swept over, "name must be a hashable type"

File "/Users/polyn/PycharmProjects/cymr_dev/tutorial.py", line 79, in
results = model.parameter_sweep(study, param, param_name, param_sweep,
File "/Users/polyn/opt/anaconda3/envs/cymr_dev/lib/python3.8/site-packages/cymr/fit.py", line 650, in parameter_sweep
results.index.rename(param_names, inplace=True)
File "/Users/polyn/opt/anaconda3/envs/cymr_dev/lib/python3.8/site-packages/pandas/core/indexes/base.py", line 1378, in rename
return self.set_names([name], inplace=inplace)
File "/Users/polyn/opt/anaconda3/envs/cymr_dev/lib/python3.8/site-packages/pandas/core/indexes/base.py", line 1325, in set_names
idx._set_names(names, level=level)
File "/Users/polyn/opt/anaconda3/envs/cymr_dev/lib/python3.8/site-packages/pandas/core/indexes/base.py", line 1245, in _set_names
raise TypeError(f"{type(self).name}.name must be a hashable type")
TypeError: Float64Index.name must be a hashable type