Fix loading Thomas Bangalter

src/example/main.cpp

@@ -8,7 +8,7 @@
 
 int main() {
     const auto ytm = YTMusic();
-    const auto results = ytm.search("arte concert");
+    const auto results = ytm.search("Thomas Bangalter");
 
     std::cout << "Found " << results.size() << " results." << std::endl;
 

src/ytmusic.cpp

@@ -72,6 +72,10 @@ watch::Playlist::Track extract_watch_track(py::handle track);
 
 template <typename T>
 inline auto extract_py_list(py::handle obj) {
+    if (obj.is_none()) {
+        return std::vector<T>();
+    }
+
     const auto list = obj.cast<py::list>();
     std::vector<T> output;