def factor_first_event(match_info, event_list, team_key):    
    """ Creates factor for an event in event_list
    
    Arguments:
    event_list: list of 'Event' objects
    team_key: string of the event type in the 'Team' object, e.g. 'firstTower'
    
    Returns:
    -1 if no event did not happen yet
    0 if red team did event
    1 if blue team did event
    """
    
    if len(event_list) > 0:
        first_event_team = match_info['teams'][0][team_key]
        return int(first_event_team)
    else:
        return -1