[Paraview] programmable filter

[andrealphus]

I've been slowly moving from v4 to v5. Is programmable filter gone? I
use to do  a lot of operations like;

 data_0 = inputs[0].CellData['data']
 data_1 = inputs[1].CellData['data']
 output.CellData.append(data_1 - data_0, 'difference')

or more complicated then simple differencing, e.g.;

 data_0 = inputs[0].CellData['data']
 data_1 = inputs[1].CellData['data']

tmp1=A * data_0^3 + B * data_0^2 + C * data_0^3

etc...

can anyone point me to where its documented how to do this now (and
please dont just say pytrhon calculator).

thanks!
ashton