code: def _download_mirbase(args, version="CURRENT"):
      
      if not args.hairpin or not args.mirna:
          logger.info("Working with version %s" % version)
          hairpin_fn = op.join(op.abspath(args.out), "hairpin.fa.gz")
          mirna_fn = op.join(op.abspath(args.out), "miRNA.str.gz")
          if not file_exists(hairpin_fn):
              cmd_h = "wget ftp://mirbase.org/pub/mirbase/%s/hairpin.fa.gz -O %s &&  gunzip -f !$" % (version, hairpin_fn)
              do.run(cmd_h, "download hairpin")
          if not file_exists(mirna_fn):
              cmd_m = "wget ftp://mirbase.org/pub/mirbase/%s/miRNA.str.gz -O %s && gunzip -f !$" % (version, mirna_fn)
              do.run(cmd_m, "download mirna")
      else:
          return args.hairpin, args.mirna
docs: Download files from mirbase