'Functions return type.'

def _set_restypes(self):

    windll.user32.GetSystemMetrics.restypes = INT
    windll.user32.EnumDisplayMonitors.restypes = BOOL
    windll.user32.GetWindowDC.restypes = HDC
    windll.gdi32.CreateCompatibleDC.restypes = HDC
    windll.gdi32.CreateCompatibleBitmap.restypes = HBITMAP
    windll.gdi32.SelectObject.restypes = HGDIOBJ
    windll.gdi32.BitBlt.restypes = BOOL
    windll.gdi32.GetDIBits.restypes = INT
    windll.gdi32.DeleteObject.restypes = BOOL
