[ALPS-users] fitting of experimental data

Dear all, in the description of ALPS there is a note about the possibility of experimental data fitting. Unfortunately, I can't find in tutorials and documentation the way how to fit, for example, experimental susceptibility data with the simulations from ALPS. In the code I've found just fit_wrapper function. Should I use it (or another) for parameter optimization or it's need to write own optimizer? Thanks in advance.