func (es Entities) SetHandle(v *int) {
	for _, e := range es {
		e.SetHandle(v)
	}
}
SetHandle sets handles to each entity.
package entity
import (
	"github.com/yofu/dxf/format"
)
type Entities []Entity
func New() Entities {
	e := make([]Entity, 0)
	return e
}
func (es Entities) Format(f format.Formatter) {
	f.WriteString(0, "SECTION")
	f.WriteString(2, "ENTITIES")
	for _, e := range es {
		e.Format(f)
	}
	f.WriteString(0, "ENDSEC")
}
func (es Entities) Add(e Entity) Entities {
	es = append(es, e)
	return es
}