Feature request: graph diagnostics

[martinctc]

It would be helpful for troubleshooting and also general network analysis if there is a handy function to return a description of the graph returned by return_type = 'network' by the ONA functions. For instance, the output can contain these checks from igraph:

g.is_simple()
g.is_directed()
g.vertex_attributes()
g.edge_attributes()
g.ecount()
g.vcount()

This could be returned as a data frame, and it could work like network_summary() where the input is an igraph Graph object.