Dual fiber with dual wavelength solution?

[regislachaume]

I've just discovered pyreduce and tried to adapt the HARPS reduction in order to:

1. get a wavelength solution for each fibre independently. For instance the harps_test_red.comb.npz would then contain an array of size (2, 26, 4096).
2. extract both fibres (STAR,WAVE,* STAR,SKY,* or STAR,DARK,*). The 'science' step would then yield spectra of shape (2, 26, 4096).

Is it possible with the json configuration or is there some coding to do? So fare, the only thing I've been able to get is to get process the frame as if there were 52 orders in the red mode but, then, the wavelength solution is bad (obviously).