code: def iteration_stats(self, k, r, s, epri, edua):
          
  
          tk = self.timer.elapsed(self.opt['IterTimer'])
          tpl = (k,) + self.eval_objfn() + (r, s, epri, edua, self.rho) + \
              self.itstat_extra() + (tk,)
          return type(self).IterationStats(*tpl)
docs: Construct iteration stats record tuple.