code: def better(old_value, new_value, mode):
      
      if (old_value is None or np.isnan(old_value)) and (new_value is not None and not np.isnan(new_value)):
          return True
  
      if mode == 'min':
          return new_value < old_value
      elif mode == 'max':
          return new_value > old_value
      else:
          raise RuntimeError(f"Mode '{mode}' value is not supported")
docs: Check if new value is better than the old value