using fill to fill BETWEEN 2 curves

Hi All, I have seen the example where the

    > pylab.fill method is used to fill in the curve for a
    > function. However, this demo fills from the function
    > value to the 0-line of the y-axis. What I want to do is
    > fill BETWEEN 2 lines (i.e. have the baseline be a curve
    > instead of y=0). Is this possible with the pylab.fill

Have you seen examples/