Returns the node with the given index if such a node currently exists in the node list.

        Arguments:
            index (int): The index of the queried node.

        Returns:
            The node with the given index if such a node currently exists in the node list,
            `None` otherwise.

def get_node(self, index: int) -> Optional[Node]:
        """
        Returns the node with the given index if such a node currently exists in the node list.

        Arguments:
            index (int): The index of the queried node.

        Returns:
            The node with the given index if such a node currently exists in the node list,
            `None` otherwise.
        """
        return self._nodes.get(index)