def _num_items_2_heatmap_square_figsize_ver2(n):
    """ uses linear regression model to infer adequate figsize
        from the number of items 
        the difference from version 1 is from very long names leading
        to a smaller figure
    Data used for training:
        X = [5,10,15,20,25,30,35,50,60]
        y = [[6,6],[8,8],[9,9],[11,11],[11,11],[12,12],[13,13],[14,14]]
    Parameters
    ----------
    n : int
        number of items
    Returns
    -------
    (w,h) : tuple
        the width and the height of the figure
    """
    w = 0.12940*n + 6.86068
    h = w
    return (int(w), int(h))