def _get_figure_size(numaxes):
    """
    Return the default figure size.
    Width: 8 units
    Height: 3 units for every subplot or max 9 units
    Return
    ------

    (width, height)
      The figure size in inches.
    """

    figure_width = 8
    figure_height = max(6, min(numaxes * 3, 10))

    return (figure_width, figure_height)