Method getAuthorisedViewLevels

/**
 * Gets an array of the authorised access levels for the user
 *
 * @return  array
 *
 * @since   1.7.0
 */
public function getAuthorisedViewLevels()
{
    if ($this->_authLevels === null) {
        $this->_authLevels = array();
    }
    if (empty($this->_authLevels)) {
        $this->_authLevels = Access::getAuthorisedViewLevels($this->id);
    }
    return $this->_authLevels;
}