[igraph] add vertex and set its attribute

[Simone Gabbriellini]

Hello list,

I am trying to add a new vertex to my network and set its type attribute to 0, 
but cannot figure out the right syntax. 
I am on igraph 0.5.3

g.add_vertices(1) should add the vertex, but how to set the type attribute of 
this new vertex to 0? 

Is there a single line  code I can use for this or should I recover the vertex 
by its id, which I suppose will be the larger in the graph?

thanks,
simone