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: operator_usage.go
    path of file: ./repos/vault/command
    
    the code of the file until where you have to start completion: // Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: BUSL-1.1

package command

import (
	"encoding/json"
	"errors"
	"fmt"
	"sort"
	"strings"
	"time"

	"github.com/hashicorp/cli"
	"github.com/hashicorp/vault/api"
	"github.com/posener/complete"
	"github.com/ryanuber/columnize"
)

var (
	_ cli.Command             = (*OperatorUsageCommand)(nil)
	_ cli.CommandAutocomplete = (*OperatorUsageCommand)(nil)
)

type OperatorUsageCommand struct {
	*BaseCommand
	flagStartTime time.Time
	flagEndTime   time.Time
}

func (c *OperatorUsageCommand) Synopsis() string {
	return "Lists historical client counts"
}

func (c *OperatorUsageCommand) Help() string {
	helpText := `
Usage: vault operator usage

  List the cl
    
func (c *OperatorUsageCommand) parseNamespaceCount(rawVal interface{}) (UsageResponse, error) {
	var ret UsageResponse

	val, ok := rawVal.(map[string]interface{})
	if !ok {
		return ret, errors.New("value is not a map")
	}

	ret.namespacePath, ok = val["namespace_path"].(string)
	if !ok {
		return ret, errors.New("bad namespace path")
	}

	counts, ok := val["counts"].(map[string]interface{})
	if !ok {
		return ret, errors.New("missing counts")
	}

	ret.entityCount, ok = jsonNumberOK(counts, "distinct_entities")
	if !ok {
		return ret, errors.New("missing distinct_entities")
	}

	ret.tokenCount, ok = jsonNumberOK(counts, "non_entity_tokens")
	if !ok {
		return ret, errors.New("missing non_entity_tokens")
	}

	// don't error if the secret syncs key is missing
	ret.secretSyncs, _ = jsonNumberOK(counts, "secret_syncs")

	ret.clientCount, ok = jsonNumberOK(counts, "clients")
	if !ok {
		return ret, errors.New("missing clients")
	}

	return ret, nil
}