code: function addInspection(type, cb) {
      // istanbul ignore next;
      if (npm.util.inspect.custom) {
          // Custom inspection is supported:
          type.prototype[npm.util.inspect.custom] = cb;
      } else {
          // Use classic inspection:
          type.prototype.inspect = cb;
      }
  }
docs: ////////////////////////////////////////////////////// Adds prototype inspection, with support of the newer Custom Inspection, which was added in Node.js 6.x