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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_used_key_frames(self):
 """Returns a list of the keyframes used by this channel, sorted with time. Each element in the list is a tuple. The first element is the key_name and the second is the channel data at that keyframe."""


        skl = self.key_frame_list.sorted_key_list()
        # each element in used_key_frames is a tuple (key_name, key_dict)
        used_key_frames = []
        for kf in skl:
            if kf in self.dct['keys']:
                used_key_frames.append((kf, self.dct['keys'][kf]))
        return used_key_frames