func (g *baseWeighted) Order() int {
	g.mu.RLock()
	defer g.mu.RUnlock()
	return len(g.list)
}
Returns the order (number of vertices) in the graph.
package al
import (
	"sync"
	. "github.com/sdboyer/gogl"
	"gopkg.in/fatih/set.v0"
)
type baseWeighted struct {
	list map[Vertex]map[Vertex]float64
	size int
	mu   sync.RWMutex
}
func (g *baseWeighted) Vertices(f VertexStep) {
	g.mu.RLock()
	defer g.mu.RUnlock()
	for v := range g.list {
		if f(v) {
			return
		}
	}
}
func (g *baseWeighted) HasVertex(vertex Vertex) (exists bool) {
	g.mu.RLock()
	defer g.mu.RUnlock()
	exists = g.hasVertex(vertex)
	return
}
func (g *baseWeighted) hasVertex(vertex Vertex) (exists bool) {
	_, exists = g.list[vertex]
	return
}