Returns the filter data for the given key.
        
        :param      key | <str>
        
        :return     <str>

def filterData(self, key):
        """
        Returns the filter data for the given key.
        
        :param      key | <str>
        
        :return     <str>
        """
        if key == 'text':
            default = nativestring(self.text())
        else:
            default = ''
        return self._filterData.get(key, default)