code: def usearch_chimera_filter_de_novo(
          fasta_filepath,
          output_chimera_filepath=None,
          output_non_chimera_filepath=None,
          abundance_skew=2.0,
          log_name="uchime_de_novo_chimera_filtering.log",
          usersort=False,
          HALT_EXEC=False,
          save_intermediate_files=False,
          remove_usearch_logs=False,
          working_dir=None):
      if not output_chimera_filepath:
          _, output_chimera_filepath = mkstemp(prefix='uchime_chimeras_',
                                               suffix='.fasta')
      if not output_non_chimera_filepath:
          _, output_non_chimera_filepath = mkstemp(prefix='uchime_non_chimeras_',
                                                   suffix='.fasta')
      log_filepath = join(working_dir, log_name)
      params = {'--abskew': abundance_skew}
      app = Usearch(params, WorkingDir=working_dir, HALT_EXEC=HALT_EXEC)
      if usersort:
          app.Parameters['--usersort'].on()
      data = {'--uchime': fasta_filepath,
              '--chimeras': output_chimera_filepath,
              '--nonchimeras': output_non_chimera_filepath
              }
      if not remove_usearch_logs:
          data['--log'] = log_filepath
      app_result = app(data)
      if not save_intermediate_files:
          remove_files([output_chimera_filepath])
      return app_result, output_non_chimera_filepath