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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 delete(self, key: bytes) -> Tuple[Hash32]: """ Equals to setting the value to None Returns all updated hashes in root->leaf order """

        validate_is_bytes(key)
        validate_length(key, self._key_size)

        return self.set(key, self._default)