code: def set(self, key, value):
      self.spark_conf = self.spark_conf.set(key, value)
      return self
  
file_path: BigDL/python/ppml/src/bigdl/ppml/utils/ppml_conf.py
imports: import os
  from pyspark import SparkConf
label_desc: Use image node_id 2 for calling the PPMLConf obj's underlying member method code with example usage: obj.set(key, value) and returns: self