func addshadow(top: Bool,
              left: Bool,
              bottom: Bool,
              right: Bool,
              shadowRadius: CGFloat) {
        self.backgroundColor = UIColor.white
        self.layer.masksToBounds = false
        self.layer.cornerRadius = 8
        self.layer.shadowOffset = CGSize(width: 0.0, height: 0.0)
        self.layer.shadowRadius = shadowRadius
        self.layer.shadowOpacity = 0.4
        self.layer.shadowColor = UIColor(red: 6.0/255, green: 141.0/255, blue: 144.0/255, alpha: 1.0).cgColor
        let path = UIBezierPath()
        var x: CGFloat = 0
        var y: CGFloat = 0
        var viewWidth = self.frame.width
        var viewHeight = self.frame.height
        // here x, y, viewWidth, and viewHeight can be changed in
        // order to play around with the shadow paths.
        if (!top) {
          y+=(shadowRadius+1)
        }
        if (!bottom) {
          viewHeight-=(shadowRadius+1)
        }
        if (!left) {
          x+=(shadowRadius+1)
        }
        if (!right) {
          viewWidth-=(shadowRadius+1)
        }
        // selecting top most point
        path.move(to: CGPoint(x: x, y: y))
        // Move to the Bottom Left Corner, this will cover left edges
        /*
         |☐
         */
        path.addLine(to: CGPoint(x: x, y: viewHeight))
        // Move to the Bottom Right Corner, this will cover bottom edge
        /*
         ☐
         -
         */
        path.addLine(to: CGPoint(x: viewWidth, y: viewHeight))
        // Move to the Top Right Corner, this will cover right edge
        /*
         ☐|
         */
        path.addLine(to: CGPoint(x: viewWidth, y: y))
        // Move back to the initial point, this will cover the top edge
        /*
         _
         ☐
         */
        path.close()
        self.layer.shadowPath = path.cgPath
      }