docs: def sort_by_abundance_usearch61(seq_path,
                                  output_dir='.',
                                  rev=False,
                                  minlen=64,
                                  remove_usearch_logs=False,
                                  HALT_EXEC=False,
                                  output_fna_filepath=None,
                                  output_uc_filepath=None,
                                  log_name="abundance_sorted.log",
                                  threads=1.0):
      """ usearch61 application call to sort fasta file by abundance.
  
      seq_path:  fasta filepath to be clustered with usearch61
      output_dir: directory to output log, OTU mapping, and intermediate files
      rev: enable reverse strand matching for clustering/sorting
      minlen: minimum sequence length
      remove_usearch_logs: Saves usearch log files
      HALT_EXEC: application controller option to halt execution
      output_fna_filepath: path to write sorted fasta filepath
      output_uc_filepath: path to write usearch61 generated .uc file
      log_name: filepath to write usearch61 generated log file
      threads: Specify number of threads used per core per CPU
      """
  
      if not output_fna_filepath:
          _, output_fna_filepath = mkstemp(prefix='abundance_sorted',
                                           suffix='.fna')
  
      if not output_uc_filepath:
          _, output_uc_filepath = mkstemp(prefix='abundance_sorted',
                                          suffix='.uc')
  
      log_filepath = join(output_dir, log_name)
  
      params = {'--minseqlength': minlen,
                '--sizeout': True,
                '--derep_fulllength': seq_path,
                '--output': output_fna_filepath,
                '--uc': output_uc_filepath,
                '--threads': threads
                }
  
      if rev:
          params['--strand'] = 'both'
      if not remove_usearch_logs:
          params['--log'] = log_filepath
  
      app = Usearch61(params, WorkingDir=output_dir, HALT_EXEC=HALT_EXEC)
  
      app_result = app()
  
      return output_fna_filepath, output_uc_filepath, app_result