func (p *Slo) PurgeOldRecords() {
	p.mu.Lock()
	defer p.mu.Unlock()
	now := time.Now()
	for t := range p.set {
		if now.Sub(t).Hours() > 2 {
			delete(p.set, t)
		}
	}
}
PurgeOldRecords removes all pages that are more than 2 hours old
package paginator
import (
	"errors"
	"fmt"
	"sync"
	"time"
	"github.com/GoogleCloudPlatform/devrel-services/leif"
	"github.com/sirupsen/logrus"
)
type sloPage struct {
	items []*leif.SLORule
	index int
}
type Slo struct {
	Log     *logrus.Logger
	mu      sync.Mutex
	set     map[time.Time]sloPage
	didInit bool
}
func (p *Slo) Init() error {
	p.mu.Lock()
	defer p.mu.Unlock()
	if p.didInit {
		return fmt.Errorf("Paginator already initialized")
	}
	p.set = make(map[time.Time]sloPage)
	p.didInit = true
	return nil
}