index ?? null; if (isset($index)) { return "/$index"; } throw new RuntimeException('Missing parameter for the endpoint indices.exists'); } public function getParamWhitelist(): array { return [ 'local', 'ignore_unavailable', 'allow_no_indices', 'expand_wildcards', 'flat_settings', 'include_defaults' ]; } public function getMethod(): string { return 'HEAD'; } }