/**
  * Creates a new Zend_Service_WindowsAzure_Credentials_SharedAccessSignature instance
  *
  * @param string $accountName Account name for Windows Azure
  * @param string $accountKey Account key for Windows Azure
  * @param boolean $usePathStyleUri Use path-style URI's
  * @param array $permissionSet Permission set
  */
 public function __construct(
     $accountName = Zend_Service_WindowsAzure_Credentials_CredentialsAbstract::DEVSTORE_ACCOUNT,
     $accountKey  = Zend_Service_WindowsAzure_Credentials_CredentialsAbstract::DEVSTORE_KEY,
     $usePathStyleUri = false, $permissionSet = array()
 ) {
     parent::__construct($accountName, $accountKey, $usePathStyleUri);
     $this->_permissionSet = $permissionSet;
 }