             newElement.title = "Item \(index)"
             
             // generate the random number between 0...childs
-            let random = Int(arc4random_uniform(UInt32(childs + 1))) + 1
+            let random = Int(arc4random_uniform(UInt32(childs + 1)))
             
             // create the array for each cell
             newElement.childs = (0..<random).enumerate().map {"Subitem \($0.index)"}

        
        // update the state of the cell.
        self.dataSource[parent].state = .Collapsed
        
        // create an array of NSIndexPath with the selected positions
        indexPaths = (index + 1...index + numberOfChilds).map { NSIndexPath(forRow: $0, inSection: 0)}

    var dataSource: [Parent]!
    
    /// Define wether can exist several cells expanded or not.
    let numberOfCellsExpanded: NumberOfCellExpanded = .One
    
    /// Constant to define the values for the tuple in case of not exist a cell expanded.
    let NoCellExpanded = (-1, -1)
