failed to execute ['dot', '-Tsvg'], make sure the Graphviz executables are on your systems' PATH

问题描述：

安装graphviz之后，使用时出现如下错误

failed to execute ['dot', '-Tsvg'], make sure the Graphviz executables are on your systems' PATH

解决方法：

1. 下载并安装graphviz

https://graphviz.gitlab.io/_pages/Download/Download_windows.html

2. 设置环境变量

(1). 设置用户环境变量

(2). 设置系统环境变量

3. 检验是否安装成功

命令行输入：dot -version

4. python安装graphviz