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: be_key_of_matcher.go
    path of file: ./repos/podman/vendor/github.com/onsi/gomega/matchers
    
    the code of the file until where you have to start completion: package matchers

import (
	"fmt"
	"reflect"

	"github.com/onsi/gomega/format"
)

type BeKeyOfMatcher struct {
	Map interface{}
}

func (matcher *BeKeyOfMatcher) Match(actual interface{}) (success bool, err error) {
	if !isMap(ma
    
func (matcher *BeKeyOfMatcher) Match(actual interface{}) (success bool, err error) {
	if !isMap(matcher.Map) {
		return false, fmt.Errorf("BeKeyOf matcher needs expected to be a map type")
	}

	if reflect.TypeOf(actual) == nil {
		return false, fmt.Errorf("BeKeyOf matcher expects actual to be typed")
	}

	var lastError error
	for _, key := range reflect.ValueOf(matcher.Map).MapKeys() {
		matcher := &EqualMatcher{Expected: key.Interface()}
		success, err := matcher.Match(actual)
		if err != nil {
			lastError = err
			continue
		}
		if success {
			return true, nil
		}
	}

	return false, lastError
}