You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: consul.go
    path of file: ./repos/docker-ce/components/engine/vendor/github.com/docker/libkv/store/consul
    
    the code of the file until where you have to start completion: package consul

import (
	"crypto/tls"
	"errors"
	"net/http"
	"strings"
	"sync"
	"time"

	"github.com/docker/libkv"
	"github.com/docker/libkv/store"
	api "github.com/hashicorp/consul/api"
)

const (
	// DefaultWatchWaitTime is how long we block for at a
	// time to check if the watched key has changed. This
	// affects the minimum time it takes to cancel a watch.
	DefaultWatchWaitTime = 15 * time.Second

	// RenewSessionRetryMax is the number of time we s
    
func (s *Consul) AtomicDelete(key string, previous *store.KVPair) (bool, error) {
	if previous == nil {
		return false, store.ErrPreviousNotSpecified
	}

	p := &api.KVPair{Key: s.normalize(key), ModifyIndex: previous.LastIndex, Flags: api.LockFlagValue}

	// Extra Get operation to check on the key
	_, err := s.Get(key)
	if err != nil && err == store.ErrKeyNotFound {
		return false, err
	}

	if work, _, err := s.client.KV().DeleteCAS(p, nil); err != nil {
		return false, err
	} else if !work {
		return false, store.ErrKeyModified
	}

	return true, nil
}