Multiple Errors getting generated when I ran this program. Below is one example of the error. Also, there are appropriate explanations or comments for the sections within the code. Error message: NameError: name 'groupslen' is not defined.

 --------------------------------------------------------------------------- NameError Traceback (most recent call last) /var/folders/5k/n2pnqq8n1ds3wt9mjj9f3k_00000gn/T/ipykernel_27519/873044394.py in  5 weightslen = len(weights) 6 valslen = len(vals) ----> 7 if (weightslen != groupslen): 8 raise ValueError('length of weights {} isnt length of groups {}'.format(weightslen, groupslen)) 9 NameError: name 'groupslen' is not defined