def GetBaseColour():
    """
    Returns the face shading colour on push buttons/backgrounds,
    mimicking as closely as possible the platform UI colours.
    """

    if wx.Platform == "__WXMAC__":

        if hasattr(wx, 'MacThemeColour'):
            base_colour = wx.MacThemeColour(Carbon.Appearance.kThemeBrushToolbarBackground)
        else:
            brush = wx.Brush(wx.BLACK)
            brush.MacSetTheme(Carbon.Appearance.kThemeBrushToolbarBackground)
            base_colour = brush.GetColour()

    else:
        
        base_colour = wx.SystemSettings.GetColour(wx.SYS_COLOUR_3DFACE)

    # the base_colour is too pale to use as our base colour,
    # so darken it a bit
    if ((255-base_colour.Red()) +
        (base_colour.Green()-255) +
        (255-base_colour.Blue()) < 60):
    
        base_colour = StepColour(base_colour, 92)
    
    return base_colour
dataset/ETHPy150Open ContinuumIO/ashiba/enaml/enaml/wx/wx_upstream/aui/aui_utilities.py/GetBaseColour/swapped operands of `-`