def METHOD_NAME(self, *args, **kwargs):
    """
    usage:
        append(green=0.1, red=0.5, blue=0.21)
    # former, now almost deprecated version:
        append(0.5, 0.6)
    """
    for k in kwargs.keys():
        v = kwargs.pop(k)
        kwargs[k[0]] = v
    i=0
    for value in args:
        while self._defaultcolors[i] in kwargs:
            i += 1
        kwargs[self._defaultcolors[i]] = value
    t = time()-self.plot_start_time
    for color, value in kwargs.items():
        if value is not None:
            if not color in self.curves:
                self.curves[color] = self.pw.plot(pen=color)
            curve = self.curves[color]
            x, y = curve.getData()
            if x is None or y is None:
                x, y = np.array([t]), np.array([value])
            else:
                x, y = np.METHOD_NAME(x, t), np.METHOD_NAME(y, value)
            curve.setData(x, y)