TraCI file has a priblem

I've written a little code in python for getting connected to sumo as follows:

    import traci
    traci.start(sumoCmd)
    step = 0
    while step < 200:
       traci.simulationStep()
       traci.vehicle.add('x', typeID='DEFAULT_VEHTYPE')
       step += 1
    traci.close()

1 - The GUI's answer is:

• Loading is done.
• Simulation started with time: 0.00** I want to know why nothing is shown in GUI?

2 - Is there any order in TraCi to say sumo do something? (describing lane, edge, route, vehicle, etc?) p.s. Sorry for my mistake in the title