Function graph_isomorphic 

pub fn graph_isomorphic<P, T, N, E>(
    left: &P,
    right: &T,
    node_match: N,
    edge_match: E,
) -> bool
where
    P: IndexGraphView,
    T: IndexGraphView,
    N: Fn(P::Node, T::Node) -> bool,
    E: Fn(P::Edge, T::Edge) -> bool,