Return a random maximal independent set guaranteed to contain a given set of nodes.
An independent set is a set of nodes such that the subgraph of G induced by these nodes contains no edges. A maximal independent set is an independent set such that it is not possible to add a new node and still get an independent set.
Parameters :  G : NetworkX graph nodes : list or iterable


Returns :  indep_nodes : list

Raises :  NetworkXUnfeasible :

Notes
This algorithm does not solve the maximum independent set problem.
Examples
>>> G = nx.path_graph(5)
>>> nx.maximal_independent_set(G)
[4, 0, 2]
>>> nx.maximal_independent_set(G, [1])
[1, 3]