new column creation based on values of another column using if- else condition on python

I am trying in following was

import numpy as np        
conditions = [
        (dfyz['year_x'] < datetime.now().year),
        ((dfyz['year_x'] == datetime.now().year) and (dfyz['mon'] < datetime.now().month)),
        (dfyz['year_x'] > datetime.now().year),
        ((dfyz['year_x'] == datetime.now().year) and (dfyz['mon'] >= datetime.now().month))
        ]   
values =  [dfyz['yhat']*dfyz['pct'], dfyz['yhat']*dfyz['pct'], dfyz['yhat']*dfyz['pct_ft'], dfyz['yhat']*dfyz['pct_ft']]
dfyz['pred_n'] = np.select(conditions,values)

but i am getting following error

f"The truth value of a {type(self).__name__} is ambiguous.

ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().

i have tried in another way also and posted in stackoverflow but there was no success so far if else not checking both of the conditions in Python