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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 handle_subscribe(self, request, path):
 # type: (Subscribe, List[str]) -> CallbackResponses """Add to the list of request to notify, and notify the initial value of the data held Args: request (Subscribe):
 The subscribe request path (list):
 The relative path from ourself Returns: list: [(callback, Response)] that need to be called """

        ret = []
        if path:
            # Recurse down
            name = path[0]
            if name not in self.children:
                self.children[name] = NotifierNode(
                    getattr(self.data, name, None), self)
            ret += self.children[name].handle_subscribe(request, path[1:])
        else:
            # This is for us
            serialized = serialize_object(self.data)
            if request.delta:
                self.delta_requests.append(request)
                ret.append(request.delta_response([[[], serialized]]))
            else:
                self.update_requests.append(request)
                ret.append(request.update_response(serialized))
        return ret