Error : a bytes-like object is required, not 'str' : ['dot', '-Tsvg']
    graph communication_overview_http_app {
      rankdir=LR;
      compound=true;
      node [shape=box fontsize=10];

      client [label="Web client\n(eg. browser)"];

      subgraph cluster_sandstorm {
        label="Sandstorm";
        proxy [label="Proxy\n (proxy.js)";];
        websession [label="WebSession Serialization\n(HTTP over Cap'n Proto,\nweb-session.capnp)"];
      }

      subgraph cluster_grain {
        label="Grain";
        bridge [label="Sandstorm\nHTTP Bridge\n(sandstorm-http\n-bridge.c++)"]
        app [label="HTTP App"];
      }

      client -- proxy;
      proxy -- websession;
      websession -- bridge;
      bridge -- app;
    }