Use of mictools

Hi,
I am using the program mictools, a correlation analysis program: GitHub - minepy/mictools: A practical tool for Maximal Information Coefficient (MIC) analysis
I am pretty sure it is installed properly, as I can run the mictools --help and the mictools null commands, but when I run mictools pval I get the following error:
Any advise for this would be greatly appreciated!

[nathanwi@e09-18 mictools]$ mictools pval potatoe_mictools_phaeocystis.df.txt null_dist.txt Results/
Traceback (most recent call last):
  File "/home1/nathanwi/.local/lib/python3.9/site-packages/pandas/core/indexes/base.py", line 3790, in get_loc
    return self._engine.get_loc(casted_key)
  File "index.pyx", line 152, in pandas._libs.index.IndexEngine.get_loc
  File "index.pyx", line 181, in pandas._libs.index.IndexEngine.get_loc
  File "pandas/_libs/hashtable_class_helper.pxi", line 7080, in pandas._libs.hashtable.PyObjectHashTable.get_item
  File "pandas/_libs/hashtable_class_helper.pxi", line 7088, in pandas._libs.hashtable.PyObjectHashTable.get_item
KeyError: 'None'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home1/nathanwi/.local/bin/mictools", line 8, in <module>
    sys.exit(cli())
  File "/home1/nathanwi/.local/lib/python3.9/site-packages/click/core.py", line 1157, in __call__
    return self.main(*args, **kwargs)
  File "/home1/nathanwi/.local/lib/python3.9/site-packages/click/core.py", line 1078, in main
    rv = self.invoke(ctx)
  File "/home1/nathanwi/.local/lib/python3.9/site-packages/click/core.py", line 1688, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home1/nathanwi/.local/lib/python3.9/site-packages/click/core.py", line 1434, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home1/nathanwi/.local/lib/python3.9/site-packages/click/core.py", line 783, in invoke
    return __callback(*args, **kwargs)
  File "/home1/nathanwi/.local/lib/python3.9/site-packages/scripts/mictools_cmd.py", line 177, in pval
    mictools.pval.pval_cmd(xvars, null, output, labels, target, yvars, rowwise, 
  File "/home1/nathanwi/.local/lib/python3.9/site-packages/mictools/pval.py", line 145, in pval_cmd
    obs_dist, obs, pval = compute_pval(X=X,
  File "/home1/nathanwi/.local/lib/python3.9/site-packages/mictools/pval.py", line 96, in compute_pval
    null_dist_cl = null_dist.loc[cl]
  File "/home1/nathanwi/.local/lib/python3.9/site-packages/pandas/core/indexing.py", line 1153, in __getitem__
    return self._getitem_axis(maybe_callable, axis=axis)
  File "/home1/nathanwi/.local/lib/python3.9/site-packages/pandas/core/indexing.py", line 1393, in _getitem_axis
    return self._get_label(key, axis=axis)
  File "/home1/nathanwi/.local/lib/python3.9/site-packages/pandas/core/indexing.py", line 1343, in _get_label
    return self.obj.xs(label, axis=axis)
  File "/home1/nathanwi/.local/lib/python3.9/site-packages/pandas/core/generic.py", line 4228, in xs
    loc, new_index = index._get_loc_level(key, level=0)
  File "/home1/nathanwi/.local/lib/python3.9/site-packages/pandas/core/indexes/multi.py", line 3175, in _get_loc_level
    indexer = self._get_level_indexer(key, level=level)
  File "/home1/nathanwi/.local/lib/python3.9/site-packages/pandas/core/indexes/multi.py", line 3276, in _get_level_indexer
    idx = self._get_loc_single_level_index(level_index, key)
  File "/home1/nathanwi/.local/lib/python3.9/site-packages/pandas/core/indexes/multi.py", line 2865, in _get_loc_single_level_index
    return level_index.get_loc(key)
  File "/home1/nathanwi/.local/lib/python3.9/site-packages/pandas/core/indexes/base.py", line 3797, in get_loc
    raise KeyError(key) from err
KeyError: 'None'
[nathanwi@e09-18 mictools]$