get the startTime and endTime of an experiment

def get_experiment_time(port):
    '''get the startTime and endTime of an experiment'''
    response = rest_get(experiment_url(port), REST_TIME_OUT)
    if response and check_response(response):
        content = convert_time_stamp_to_date(json.loads(response.text))
        return content.get('startTime'), content.get('endTime')
    return None, None