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: build.go
    path of file: ./repos/podman/vendor/github.com/containers/buildah/pkg/cli
    
    the code of the file until where you have to start completion: package cli

// the cli package contains spf13/cobra related 
    
func readBuildArg(buildarg string, args map[string]string) {
	av := strings.SplitN(buildarg, "=", 2)
	if len(av) > 1 {
		args[av[0]] = av[1]
	} else {
		// check if the env is set in the local environment and use that value if it is
		if val, present := os.LookupEnv(av[0]); present {
			args[av[0]] = val
		} else {
			delete(args, av[0])
		}
	}
}