Goes down one level if possible and returns the url at the current \
        level.  If it cannot go down, then a blank string will be returned.
        
        :return     <str>

def goForward(self):
        """
        Goes down one level if possible and returns the url at the current \
        level.  If it cannot go down, then a blank string will be returned.
        
        :return     <str>
        """
        if not self.canGoForward():
            return ''
        
        self._blockStack = True
        self._index += 1
        self.emitCurrentChanged()
        self._blockStack = False
        return self.currentUrl()