[E<lt>B<L<data calculation|rrdgraph_data/CDEF>>E<gt> ...]
[E<lt>B<L<variable definition|rrdgraph_data/VDEF>>E<gt> ...]
[E<lt>B<L<graph element|rrdgraph_graph/GRAPH>>E<gt> ...]
[E<lt>B<L<data calculation|rrdgraph_data/CDEF>>E<gt> ...]
[E<lt>B<L<variable definition|rrdgraph_data/VDEF>>E<gt> ...]
[E<lt>B<L<graph element|rrdgraph_graph/GRAPH>>E<gt> ...]