size_t n_playlists(ARDOUR::DataType t) const { return get_n(t, _playlists); }
size_t n_regions(ARDOUR::DataType t) const { return get_n(t, _regions); }
size_t n_lines(Evoral::Parameter t) const { return get_n(t, _lines); }
size_t n_playlists(ARDOUR::DataType t) const { return get_n(t, _playlists); }
size_t n_regions(ARDOUR::DataType t) const { return get_n(t, _regions); }
size_t n_lines(Evoral::Parameter t) const { return get_n(t, _lines); }