attribute xstart not found in cell

[Dalila17To]

Hi, running the notebook with allen models data I've received an error "AttributeError: 'Cell' object has no attribute 'xstart'. Did you mean: 'tstart'? dlopen failed -". Actually xstart and so on aren't in the directory of cell. Should I calculate them manually or is there a problem with the version of neuron or LFPy that I have installed? Thanks in advance