def _add_aeration_to_growth_model(aer, model):
    if isinstance(aer, Process):
        processes = Processes(model.tuple)
        processes.append(aer)
        processes.compile()
    else:
        processes = model
        processes.compile()
    return processes
def _add_aeration_to_growth_model(aer, model):
    if isinstance(aer, Process):
        processes = Processes(model.tuple)
        processes.append(aer)
        processes.compile()
    else:
        processes = model
        processes.compile()
    return processes