code: def __add__(self, other):
      new_importance = FeatureImportance(gain=self.gain + other.gain)
      new_importance.split = self.split + other.split
      return new_importance
  
imports: import numpy
  import pandas
  from fate.arch import Context
  from fate.arch.dataframe import DataFrame
  from fate.ml.ensemble.learner.decision_tree.tree_core.splitter import SplitInfo
  from typing import List
  import logging
label_desc: Use image node_id 5 for calling the FeatureImportance obj's underlying member method code with example usage: obj.__add__(other) and returns: new_importance