code: def intersect(database_1, database_2, results, returncmd=False):
      
      cmd = 'kmc_tools intersect {} {} {}'.format(database_1, database_2, results)
      out, err = accessoryfunctions.run_subprocess(cmd)
      if returncmd:
          return out, err, cmd
      else:
          return out, err
docs: Finds kmers that are present in 2 databases.
      :param database_1: First database generated by kmc.
      :param database_2: Second database generated by kmc.
      :param results: Result database, containing reads in both database 1 and 2.
      :param returncmd: If true, will return the command used to call KMC as well as out and err.
      :return: Stdout and stderr from kmc.