func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: String.init(describing: MADCalendarCell.self), for: indexPath) as! MADCalendarCell
        
        if indexPath.row < self.weekTitles.count {
            cell.titleLabel.text = self.weekTitles[indexPath.row]
        }else {
            let index = indexPath.row - self.weekTitles.count
            if index < self.currentMonthData.dayArr.count {                
                cell.model = self.currentMonthData.dayArr[index]
            }
        }
        return cell
    }