If you're trying to use a package make sure that '../../static/fonts/lato/Lato-Regular.woff' is installed. If you're trying to use a local file make sure that the path is correct.
link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous"