CODE EXAMPLE FOR SHELL

tree implementation in python

class Tree:
  def __init__(self, val = None):
    if val != None:
	    self.val = val
    else:
        self.val = None
    self.left = None
    self.right = None

  def insert(self, val):
    if self.val:
        if val < self.val:
            if self.left is None:
            	self.left = Tree(val)
            else:
            	self.left.insert(val)
        elif val > self.val:
        		if self.right is None:
              self.right = Tree(val)
            else:
              self.right.insert(val)
    else:
        self.val = val

  def printValues(self):
    if self.left:
        self.left.printValues()
    print(self.val)
    if self.right:
        self.right.printValues()

tree = Tree(20)
tree.left = Tree(18)
tree.right = Tree(22)
tree.insert(19)
tree.insert(24)
tree.insert(5)
tree.insert(21)

tree.printValues()