def columns_used(self):
        return list(tz.unique(tz.concat(
            m.columns_used() for m in self.models.values())))
Reads a block from the simple spike data file "fname" generated
dataset/ETHPy150Open UDST/urbansim/urbansim/models/dcm.py/MNLDiscreteChoiceModelGroup.columns_used--crossover with--dataset/ETHPy150Open NeuralEnsemble/python-neo/neo/io/brainwaref32io.py/BrainwareF32IO.read_block