def update(self, event = None):
        dc = wx.ClientDC(self)
        #if we have a custom background, we *must* set the background brush *BEFORE* clearing...
        dc.SetBackground(wx.Brush(wx.Colour(255,255,255), wx.SOLID))
        dc.Clear()

        for channel in self.channels:
            channel.paint(dc)
Override this method to use a different test_func method.
dataset/ETHPy150Open enthought/mayavi/tvtk/util/wx_gradient_editor.py/wxFunctionControl.update--crossover with--dataset/ETHPy150Open django/django/django/contrib/auth/mixins.py/UserPassesTestMixin.get_test_func