I am trying to value inflation swaps using necessary functions from quantlib and successfully completed the valuation. Underneath helper function is working well for most of the swaps. But few swaps giving me below error. RuntimeError: more than one instrument with pillar May 17th, 2021.
helpers =  for idx, row in rate_data.iterrows(): rate = row["mid_yield"] / 100 tenor = row.tenor if tenor == "1D": helpers.append(ql.DepositRateHelper(rate, index)) else: helpers.append( ql.OISRateHelper( 0, ql.Period(tenor), ql.QuoteHandle(ql.SimpleQuote(rate)), index ) )
I know the maturity dates from 'helper' is colliding with the maturity dates of rates. I just want to know how to print the variables/dates/pillars from 'helpers' in python to see the dates. Thereafter I can do further analysis based on constructed helpers maturity dates.