code: def _init_spark(self):
          
          global _SPARK_INITIALIZED
          spark_home = self.spark_home
          python_path = self._python_path
  
          if use_findspark:
              if _SPARK_INITIALIZED:
                  if spark_home == os.environ["SPARK_HOME"]:
                      # matches with already initialized
                      pass
                  else:
                      # findspark adds two path to the search path.
                      sys.path.pop(0)
                      sys.path.pop(0)
                      findspark.init(spark_home=spark_home, edit_rc=False, edit_profile=False, python_path=python_path)
              else:
                  findspark.init(spark_home=spark_home, edit_rc=False, edit_profile=False, python_path=python_path)
  
          _SPARK_INITIALIZED = True
          self._set_environment_variables()
docs: Initializes spark so that pyspark is importable.  This also sets up the required environment variables