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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 add_hook(self, key_name, hook_name, hook_dict):
 """Add hook to the keyframe key_name."""

        kf = self.dct[key_name]
        if 'hooks' not in kf:
            kf['hooks'] = {}
        kf['hooks'][str(hook_name)] = hook_dict