code: def write_otu_file(otu_ids, fp):
      
      fpdir = osp.split(fp)[0]
  
      if not fpdir == "" and not osp.isdir(fpdir):
          raise RuntimeError("Specified path does not exist: {}".format(fpdir))
  
      with open(fp, 'wt') as outf:
          outf.write('\n'.join(otu_ids))
docs: Write out a file containing only the list of OTU IDs from the kraken data.
      One line per ID.
  
      :type otu_ids: list or iterable
      :param otu_ids: The OTU identifiers that will be written to file.
      :type fp: str
      :param fp: The path to the output file.