$4.$Write a method is$\_$balanced in LinkedBST which

determines if the tree is balanced or not. This method should

traverse the tree and check to see if any Node is the root of

an unbalanced subtree. If you find an unbalanced Node,

return False. If the whole tree is traversed and no

unbalanced Nodes are found, return True.

Hint:You can reuse some of your code from breadth in

this method to traverse the tree. Or if you prefer, you can

reuse some of the code from inorder.

class AbstractCollection:

def init$($self$,$ source$\_$collection$=$None$)$:

$"""$ Sets the initial state of self, which includes the contents of source$\_$collection $"""$

self.$\_$size $=0$

if source$\_$collection:

for item in source$\_$collection:

self.add$($item$)$

def len$($self$)$:

$"""$ Return the number of items in this collection $"""$

return self.$\_$size

def is$\_$empty$($self$)$:

$"""$ Returns True if the collection is empty and False otherwise $"""$

return len$($self$)==0$

def add$($self$,$ other$)$:

$"""$ Overloads the $+$ operator. A new collection is created with everything from self and other. $"""$

result $=$ type$($self$)($self$)$

for item in other:

result.add$($item$)$

return result

class Node:

$"""$ Represents a Node in a singly$-$linked list $"."$

def init$($self$,$ data, next$=$None$)$:

$"""$ By default, this Node will not link to another Node $"""$

self.data $=$ data

self.next $=$ next

class BinaryNode:

def init$($self$,$ data, left$=$None, right$=$None$)$:

$"""$ By default, this Node will not have any children $"""$

self.data $=$ data

self.left $=$ left

self.right $=$ right