docs: function _processName(pfx, eltDescName) {
      if (pfx === undefined || pfx === null) {
          pfx = EMPTY;
      }
      if (eltDescName === undefined || eltDescName === null) {
          return pfx;
      }
      if (pfx === EMPTY) {
          return eltDescName;
      }
      return pfx + '.' + eltDescName;
  }