use crate::graph::VertexHandle;
pub trait VertexSet {
type Vertices<'a>: Iterator<Item = VertexHandle>
where
Self: 'a;
fn vertices(&self) -> Self::Vertices<'_>;
}
pub trait VertexSetMut: VertexSet {
fn add_vertex(&mut self, handle: VertexHandle) -> bool;
fn remove_vertex(&mut self, handle: VertexHandle) -> bool;
}