Return the Caro-Wei disparity of the graph.

The Caro-Wei disparity of a graph is defined as:

\[\sum_{v \in V(G)}\frac{1}{1 + disp(v)}\]

where V(G) is the set of nodes of G and disp(v) is the disparity of the vertex v.

This invariant is inspired by the Caro-Wei bound for the independence number of a graph, hence the name.

Parameters:G (NetworkX graph) – An undirected graph.
Returns:The Caro-Wei disparity of the graph.
Return type:float