gistfile1.txt

    override func prepare(){
        super.prepare()
        guard let cv = collectionView else {return}
        let padding:CGFloat = 20.0
        self.sectionInset  = UIEdgeInsets(top: self.minimumInteritemSpacing, left: padding, bottom: 0.0, right: padding)
        self.itemSize = CGSize(width: (cv.frame.size.width - self.sectionInset.left - self.sectionInset.right - cv.contentInset.left - cv.contentInset.right)  , height: 350)
    }