public function getKeyValue($key)
    {
        return empty($this->_data[$key]) ? null: $this->_data[$key];
    }
public function getKeyValue($key)
    {
        return empty($this->_data[$key]) ? null: $this->_data[$key];
    }
public function getKeyValue ( $ key ) { return empty ( $ this -> _data [ $ key ] ) ? null : $ this -> _data [ $ key ] ; }
Get data value by key

@param mixed $key
@return mixed
Get data value by key