Function get

get(graph, key): Collections.Graphs.Directed.Vertex | undefined
Returns Vertex under key, or undefined if not found.
```
// Same as
g.vertices.get(key)
```
Parameters
- graph: Readonly<{
      vertices: IMapImmutable<string, Readonly<{
          id: string;
          out: readonly Readonly<{
              id: string;
              weight?: number;
          }>[];
      }>>;
  }>
- key: string
Returns Collections.Graphs.Directed.Vertex | undefined