What is the fine-grained topic of the following text: From 2015 to 2017, Music Excellence London ran as a dynamic network of classroom music teachers, music education hubs, cultural organisations, and the wider music education community, supporting excellent musical teaching and learning at Key Stage 3 in London schools. Only return the topic.
Music Excellence London's support for music teaching and learning at Key Stage 3 in London schools from 2015 to 2017.