code: def _get_s3_files(local_dir, file_info, params):
      
      assert len(file_info) == 1
      files = file_info.values()[0]
      fnames = []
      for k in ["1", "2"]:
          if files[k] not in fnames:
              fnames.append(files[k])
      out = []
      for fname in fnames:
          bucket, key = fname.replace("s3://", "").split("/", 1)
          if params["access_key_id"] == "TEST":
              out.append(os.path.join(local_dir, os.path.basename(key)))
          else:
              out.append(s3.get_file(local_dir, bucket, key, params))
      return out
docs: Retrieve s3 files to local directory, handling STORMSeq inputs.