docs: function install() {
    if (process.platform == 'linux') {
      if (!spawnSync('apt-get', ['-v']).error) {
        console.log("apt-get install graphviz")
        p = exec("apt-get install graphviz")
        p.stderr.pipe(process.stderr)
        p.stdout.pipe(process.stdout)
  
      } else {
        console.log("sorry only apt-get supported right now for automatic install")
        console.log("You have to install the following packages:")
        console.log("  - graphviz")
      }
    } else if (process.platform == 'darwin') {
      if (!spawnSync('brew', ['-v']).error) {
        console.log("brew install graphviz")
        p = exec("brew install graphviz")
        p.stderr.pipe(process.stderr)
        p.stdout.pipe(process.stdout)
      } else {
        console.log("You have to install Homebrew from http://brew.sh first")
      }
    } else {
      console.log("Sorry, your system is not supported for automatic install")
      console.log("You have to install the following packages:")
      console.log("  - graphviz")
    }
  }