Python 3. Никак не пойму в чем ошибка состоит

IndentationError: expected an indented block

Это происходит из за:

 def play(self):
        current_scene = self.scene_map.opening_scene()
        last_scene = self.scene_map.next_scene('finished')
    while current_scene != last_scene:

Нужно:

 def play(self):
        current_scene = self.scene_map.opening_scene()
        last_scene = self.scene_map.next_scene('finished')
        while current_scene != last_scene:

Или:

def play(self):
    current_scene = self.scene_map.opening_scene()
    last_scene = self.scene_map.next_scene('finished')
    return current_scene, last_scene 
last_scene, last_scene = self.play()
while current_scene != last_scene:

class Engine(object):
    def __init__(self, scene_map):
        self.scene_map = scene_map
    def play(self):
        current_scene = self.scene_map.opening_scene()
        last_scene = self.scene_map.next_scene('finished')
        while current_scene != last_scene:
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