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: map.go
    path of file: ./repos/faas-netes/vendor/sigs.k8s.io/structured-merge-diff/v4/value
    
    the code of the file until where you have to start completion: /*
Copyright 2019 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific langu
    
func unorderedMapZip(a Allocator, lhs, rhs Map, fn func(key string, lhs, rhs Value) bool) bool {
	if (lhs == nil || lhs.Empty()) && (rhs == nil || rhs.Empty()) {
		return true
	}

	if lhs != nil {
		ok := lhs.IterateUsing(a, func(key string, lhsValue Value) bool {
			var rhsValue Value
			if rhs != nil {
				if item, ok := rhs.GetUsing(a, key); ok {
					rhsValue = item
					defer a.Free(rhsValue)
				}
			}
			return fn(key, lhsValue, rhsValue)
		})
		if !ok {
			return false
		}
	}
	if rhs != nil {
		return rhs.IterateUsing(a, func(key string, rhsValue Value) bool {
			if lhs == nil || !lhs.Has(key) {
				return fn(key, nil, rhsValue)
			}
			return true
		})
	}
	return true
}