How each work in this situation? Why there is no parenthesis?

    public function handle(): void
    {
        User::where('email_verified_at', null)
            ->where('updated_at', '<', now()->subDay())
            ->whereDoesntHave('links', function (Builder $query): void {
                $query->where('created_at', '<', now()->subDay());
            })
            ->whereDoesntHave('questionsSent', function (Builder $query): void {
                $query->where('created_at', '<', now()->subDay());
            })
            ->whereDoesntHave('questionsReceived', function (Builder $query): void {
                $query->where('created_at', '<', now()->subDay());
            })
            ->get()
            ->each
            ->purge();
    }