Access Python blueprints with bounds checking

LibCarla/source/carla/client/BlueprintLibrary.h

@@ -47,6 +47,10 @@ namespace client {
       return _blueprints[pos];
     }
 
+    const_reference at(size_type pos) const {
+      return _blueprints.at(pos);
+    }
+
     const_iterator begin() const /*noexcept*/ {
       return _blueprints.begin();
     }

PythonAPI/source/libcarla/Blueprint.cpp

@@ -106,7 +106,7 @@ void export_blueprint() {
   class_<cc::BlueprintLibrary, boost::noncopyable, boost::shared_ptr<cc::BlueprintLibrary>>("BlueprintLibrary", no_init)
     .def("filter", &cc::BlueprintLibrary::Filter)
     .def("__getitem__", +[](const cc::BlueprintLibrary &self, size_t pos) -> cc::ActorBlueprint {
-      return self[pos];
+      return self.at(pos);
     })
     .def("__len__", &cc::BlueprintLibrary::size)
     .def("__iter__", range(&cc::BlueprintLibrary::begin, &cc::BlueprintLibrary::end))