if errors.Is(err, syscall.EADDRINUSE) {
		return ErrPortAlreadyInUse(err).Msg("Specified port is already in use")
	} else if errors.Is(err, syscall.EACCES) || errors.Is(err, syscall.EPERM) {
		if netErr, ok := err.(*net.OpError); ok {
			return ErrPortAccess(netErr).Msg("Insufficient permissions to use specified port")
		}
	}

	// Failed to identify what type of error this, return a simple UI error
	return Err{msg: err.Error()}
}

        Graph graph = new Graph();
        graph.addEdge("a1", "a2");
        assertThrows(Graph.CycleDetectedException.class, () -> graph.addEdge("a2", "a1"));
    }

    @Test
    public void testPerf() throws IOException {
        List<String[]> data = new ArrayList<>();
        String k = null;
        for (String line : Files.readAllLines(Paths.get("src/test/resources/dag.txt"))) {
            if (line.startsWith("\t")) {

// Pantheon Systems, Inc. : https://pantheon.io/
// Submitted by Gary Dylina <******@****.***>
gotpantheon.com
pantheonsite.io

// Paywhirl, Inc : https://paywhirl.com/
// Submitted by Daniel Netzer <******@****.***>
*.paywhirl.com

// pcarrier.ca Software Inc: https://pcarrier.ca/
// Submitted by Pierre Carrier <******@****.***>
*.xmit.co
xmit.dev
madethis.site
srv.us
gh.srv.us