fkooman\OAuth\Client\Scope::validateScopeToken PHP Method

    private function validateScopeToken($scopeToken)
    {
        if (!is_string($scopeToken) || 0 >= strlen($scopeToken)) {
            throw new ScopeException('scope token must be a non-empty string');
        }
        $scopeTokenRegExp = '/^(?:\\x21|[\\x23-\\x5B]|[\\x5D-\\x7E])+$/';
        $result = preg_match($scopeTokenRegExp, $scopeToken);
        return 1 === $result;
    }