Takes an arbitrary amount of Graphs or PipeOps (or objects that can be automatically
converted into Graphs or PipeOps, see as_graph() and as_pipeop()) as inputs and joins
them in a new Graph.
The PipeOps of the input Graphs are not joined with new edges across
Graphs, so if length(graphs) > 1 the resulting Graph will be disconnected.
gunion(graphs)Other Graph operators:
%>>%(),
as_graph(),
as_pipeop(),
assert_graph(),
assert_pipeop(),
greplicate(),
pipeline_greplicate()