code: def clean_cpp(self, dirty_string):
      contamination_indices = janitor_util.clean_ngram_with_indices(
          dirty_string, self.delete_chars, self.ngram_n
      )
      return self._split_chunks(dirty_string, contamination_indices)
  
imports: import re
  import string
  import timeit
  import pickle
  import traceback
  from pprint import pprint
label_desc: Use image node_id 8 for calling the Janitor obj's underlying member method code with example usage: obj.clean_cpp(dirty_string) and returns: self