Finding levels in an array of floats
You could define a window (distance between red and blue line) and slide it from top to bottom over the y-axis and then count the local minima and maxima in that slice. One way with scipy is argrelextrema(x, np.less) for minima and argrelextrema(x, np.greater) for maxima which gives you the indices of the extrema. With len(argrelextrema(x, np.less)) you would get the number of minima.

Each slice would be a level and the results of counting the minima and maxima the corresponding importance. The size of the window is up to you. If your data is very granular you might want to consider smoothing it first (e.g. with numpy.convolve()