public function contact($nameOrEmail)
    {
        if ($this->contacts === null) {
            $this->getContacts();
        }

        foreach ($this->contacts as $c) {
            if ($c->name == $nameOrEmail || $c->email == $nameOrEmail) {
                return $c;
            }
        }

        throw new Exceptions\NotFoundException("Contact not found.");
    }