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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 to_dict_hook(obj):
 """Convert internal objects to a serializable representation. During serialization if the object has the hook method `to_dict` it will be automatically called and metadata for decoding will be added. This allows for the translation of objects trees of arbitrary depth. E.g.: '{ "_type": "Root", "left": {"_type": "Node", "value": "node"}, "right": {"_type": "Node", "value": "node"} }' """

    if hasattr(obj, 'to_dict'):
        result = obj.to_dict()
        assert isinstance(result, dict), 'to_dict must return a dictionary'
        result['_type'] = f'{obj.__module__}.{obj.__class__.__name__}'
        result['_version'] = 0
        return result

    raise TypeError(
        f'Object of type {obj.__class__.__name__} is not JSON serializable',
    )