code: def hdrval(cls):
          
  
          hdrmap = {'Itn': 'Iter', 'X r': 'PrimalRsdl', 'X s': 'DualRsdl',
                    u('X ρ'): 'Rho', 'D cnstr': 'Cnstr', 'D dlt': 'DeltaD',
                    u('D η'): 'Eta'}
          return hdrmap
docs: Construct dictionary mapping display column title to
          IterationStats entries.