Instantiate an internal node.
Instantiate an internal node.
The ordering that is applied to key values
The ordering that is applied to key values
create a new Black node from a key, value, left subtree and right subtree
create a new Black node from a key, value, left subtree and right subtree
Obtain the node stored at a given key if it exists, None otherwise
create a new Red node from a key, value, left subtree and right subtree
create a new Red node from a key, value, left subtree and right subtree