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: 33_alter_configs.go
    path of file: ./repos/franz-go/pkg/kfake
    
    the code of the file until where you have to start completion: package kfake

import (
	"strconv"

	"github.com/twmb/franz-go/pkg/kerr"
	"github.com/twmb/franz-go/pkg/kmsg"
)

func init() { regKey(33, 0, 2) }

func (c *Cluster) handleAlterConfigs(b *broker, kreq kmsg.Request) (kmsg.Response, error) {
	req := kreq.(*km
    
func (c *Cluster) handleAlterConfigs(b *broker, kreq kmsg.Request) (kmsg.Response, error) {
	req := kreq.(*kmsg.AlterConfigsRequest)
	resp := req.ResponseKind().(*kmsg.AlterConfigsResponse)

	if err := checkReqVersion(req.Key(), req.Version); err != nil {
		return nil, err
	}

	doner := func(n string, t kmsg.ConfigResourceType, errCode int16) *kmsg.AlterConfigsResponseResource {
		st := kmsg.NewAlterConfigsResponseResource()
		st.ResourceName = n
		st.ResourceType = t
		st.ErrorCode = errCode
		resp.Resources = append(resp.Resources, st)
		return &resp.Resources[len(resp.Resources)-1]
	}

outer:
	for i := range req.Resources {
		rr := &req.Resources[i]
		switch rr.ResourceType {
		case kmsg.ConfigResourceTypeBroker:
			id := int32(-1)
			if rr.ResourceName != "" {
				iid, err := strconv.Atoi(rr.ResourceName)
				id = int32(iid)
				if err != nil || id != b.node {
					doner(rr.ResourceName, rr.ResourceType, kerr.InvalidRequest.Code)
					continue outer
				}
			}
			var invalid bool
			for i := range rr.Configs {
				rc := &rr.Configs[i]
				invalid = invalid || !c.setBrokerConfig(rc.Name, rc.Value, true)
			}
			if invalid {
				doner(rr.ResourceName, rr.ResourceType, kerr.InvalidRequest.Code)
				continue
			}
			doner(rr.ResourceName, rr.ResourceType, 0)
			if req.ValidateOnly {
				continue
			}
			c.bcfgs = make(map[string]*string)
			for i := range rr.Configs {
				rc := &rr.Configs[i]
				c.setBrokerConfig(rc.Name, rc.Value, false)
			}

		case kmsg.ConfigResourceTypeTopic:
			if _, ok := c.data.tps.gett(rr.ResourceName); !ok {
				doner(rr.ResourceName, rr.ResourceType, kerr.UnknownTopicOrPartition.Code)
				continue
			}
			var invalid bool
			for i := range rr.Configs {
				rc := &rr.Configs[i]
				invalid = invalid || !c.data.setTopicConfig(rr.ResourceName, rc.Name, rc.Value, true)
			}
			if invalid {
				doner(rr.ResourceName, rr.ResourceType, kerr.InvalidRequest.Code)
				continue
			}
			doner(rr.ResourceName, rr.ResourceType, 0)
			if req.ValidateOnly {
				continue
			}
			delete(c.data.tcfgs, rr.ResourceName)
			for i := range rr.Configs {
				rc := &rr.Configs[i]
				c.data.setTopicConfig(rr.ResourceName, rc.Name, rc.Value, false)
			}

		default:
			doner(rr.ResourceName, rr.ResourceType, kerr.InvalidRequest.Code)
		}
	}

	return resp, nil
}