How to remove model timespan

[TorkelE]

I got an

raise SimulationError(
gillespy2.core.gillespyError.SimulationError: argument 'solver=<gillespy2.solvers.cpp.ode_c_solver.ODECSolver object at 0x7826599b2ea0>' to run() failed.  Reason Given: 
                Failed while preparing to run the model. Both increment and timespan are set.

                To continue either remove your `timespan` definition from your Model or remove the
                `increment` argument from this `solver.run()` call.

error when running an old file. I would like to remove the timespan, but am not really sure how I do it (the model is loaded from SBML, so I don;t set it myself).