This file contains an abstract 'leaf'. A leaf is part of a tree structure
The root of the tree is a leaf, which houses other leaves, that house other leaves etc. This can sometimes be a more efficient way of storing a tree structure that is easily traversable down, such as a file system tree.
There is no branch object connecting them, the branch is 'in the leaf' itself.
Like a node, each leaf has an identifier associated with it.
NOTE: It is possible to connect one leaf to multiple leafs. This keeps track of data going down, not up.
| AbstractLeaf | Abstract Leaf Class - Defines A Leaf/Branch Structure |