AttributeError: 'NoneType' object has no attribute 'split'

[ek-chai-dena]

I am trying to run the following code but after running psm.knn_matched command I am seeing the attributeError

psm = PsmPy(psm_final, treatment='bucket_numeric', indx='pat_id', exclude = ['BUCKET'])

psm.logistic_ps(balance = True)

psm.knn_matched(matcher='propensity_logit', replacement=True, caliper=None, drop_unmatched=True)

All my values are float and int (except pat_id and the excluded column bucket)
There are no NAs in the dataframe.