code: def process_result(self, new_sia, min_sia):
          
          if new_sia.phi == 0:
              self.done = True  # Short-circuit
              return new_sia
  
          elif new_sia < min_sia:
              return new_sia
  
          return min_sia
docs: Check if the new SIA has smaller |big_phi| than the standing
          result.