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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 del_unused_keyframes(self):
 """Scans through list of keyframes in the channel and removes those which are not in self.key_frame_list."""

        skl = self.key_frame_list.sorted_key_list()
        unused_keys = [k for k in self.dct['keys']
                       if k not in skl]
        for k in unused_keys:
            del self.dct['keys'][k]