Fix loading the "Systemabsturz" artist page

src/example/main.cpp

@@ -8,7 +8,7 @@
 
 int main() {
     const auto ytm = YTMusic();
-    const auto results = ytm.search("y2ECgOhoDGs");
+    const auto results = ytm.search("Systemabsturz");
 
     std::cout << "Found " << results.size() << " results." << std::endl;
 
@@ -55,6 +55,12 @@ int main() {
                     if (playlist.lyrics) {
                         ytm.get_lyrics(*playlist.lyrics);
                     }
+                } else if (!arg.artists.empty()) {
+                    for (const meta::Artist &artist : arg.artists) {
+                        if (artist.id) {
+                            ytm.get_artist(*artist.id);
+                        }
+                    }
                 }
             } else {
                 std::cout << "non exaustive visitor" << std::endl;

src/ytmusic.cpp

@@ -205,6 +205,9 @@ playlist::Track extract_playlist_track(py::handle track) {
 }
 
 artist::Artist::Song::Album extract_song_album(py::handle album) {
+    if (album["id"].is_none()) {
+        return {};
+    }
     return {
         album["name"].cast<std::string>(),
         album["id"].cast<std::string>()