func LabelSelectorAsSelector(ps *LabelSelector) (labels.Selector, error) {
	if ps == nil {
		return labels.Nothing(), nil
	}
	if len(ps.MatchLabels)+len(ps.MatchExpressions) == 0 {
		return labels.Everything(), nil
	}
	requirements := make([]labels.Requirement, 0, len(ps.MatchLabels)+len(ps.MatchExpressions))
	for k, v := range ps.MatchLabels {
		r, err := labels.NewRequirement(k, selection.Equals, []string{v})
		if err != nil {
			return nil, err
		}
		requirements = append(requirements, *r)
	}
	for _, expr := range ps.MatchExpressions {
		var op selection.Operator
		switch expr.Operator {
		case LabelSelectorOpIn:
			op = selection.In
		case LabelSelectorOpNotIn:
			op = selection.NotIn
		case LabelSelectorOpExists:
			op = selection.Exists
		case LabelSelectorOpDoesNotExist:
			op = selection.DoesNotExist
		default:
			return nil, fmt.Errorf("%q is not a valid pod selector operator", expr.Operator)
		}
		r, err := labels.NewRequirement(expr.Key, op, append([]string(nil), expr.Values...))
		if err != nil {
			return nil, err
		}
		requirements = append(requirements, *r)
	}
	selector := labels.NewSelector()
	selector = selector.Add(requirements...)
	return selector, nil
}
LabelSelectorAsSelector converts the LabelSelector api type into a struct that implements
labels.Selector
Note: This function should be kept in sync with the selector methods in pkg/labels/selector.go
package v1
import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"k8s.io/apimachinery/pkg/fields"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/selection"
	"k8s.io/apimachinery/pkg/types"
)