for t in [t for t in game.things if t.type_ == 'Player' and t.name == nick]:
raise GameError('name already in use')
if game.get_player(connection_id):
for t in [t for t in game.things if t.type_ == 'Player' and t.name == nick]:
raise GameError('name already in use')
if game.get_player(connection_id):