code: def merge_accumulators(self, accumulators):
      return sum(accumulators)
  
file_path: pipelinedp/examples/experimental/beam_combine_fn.py
imports: from absl import app
  from absl import flags
  import apache_beam
  from apache_beam.runners.portability import fn_api_runner
  import pipeline_dp
  from pipeline_dp import private_beam
  from examples.movie_view_ratings.common_utils import ParseFile
  import numpy
  from pydp.algorithms import numerical_mechanisms
label_desc: Use image node_id 4 for calling the DPSumCombineFn obj's underlying member method code with example usage: obj.merge_accumulators(accumulators) and returns: sum