我在函数调用方面遇到问题rootBundle.loadString($path)。我想从 yaml 文件资产加载配置并在我的Web 应用程序Config的基础上创建自定义对象。但我收到错误。我无法解决这个问题，有人遇到过类似的问题吗？Unexpected null value
扑医生：
\n[\xe2\x9c\x93] Flutter (Channel master, 2.3.0-17.0.pre.225, on Ubuntu 18.04.5 LTS 5.4.0-74-generic, locale pl_PL.UTF-8)\n \xe2\x80\xa2 Flutter version 2.3.0-17.0.pre.225 at /opt/flutter\n \xe2\x80\xa2 Upstream repository https://github.com/flutter/flutter.git\n \xe2\x80\xa2 Framework revision 2794dea0df (3 days ago), 2021-06-05 16:04:04 -0400\n \xe2\x80\xa2 Engine revision 03d645e782\n \xe2\x80\xa2 Dart version 2.14.0 (build 2.14.0-182.0.dev)\n\n[!] Android toolchain - develop for Android devices (Android SDK version 29.0.3)\n \xe2\x80\xa2 Android SDK at /usr/lib/android-sdk\n \xe2\x80\xa2 Platform android-30, build-tools 29.0.3\n \xe2\x80\xa2 …