Tree_usingReferences.py

class BinaryTree:
    def __init__(self, root):
        self.key = root
        self.left_child = None
        self.right_child = None
        
    def insert_left(self, new_node):
        if self.left_child == None:
            self.left_child = BinaryTree(new_node)
        else:
            t = BinaryTree(new_node)
            t.left_child = self.left_child
            self.left_child = t
            
    def insert_right(self, new_node):
        if self.right_child == None:
            self.right_child = BinaryTree(new_node)
        else:
            t = BinaryTree(new_node)
            t.right_child  = self.right_child
            self.right_child = t
    
    def get_right_child(self):
        return self.right_child
    
    def get_left_child(self):   
        return self.left_child
    
    def set_root_val(self, value):
        self.key =value
    
    def get_root_val(self):
        return self.key
        
r = BinaryTree('a')
print(r.get_root_val())
print(r.get_left_child())
r.insert_left('b')
print(r.get_left_child())
print(r.get_left_child().get_root_val())
r.insert_right('c')
print(r.get_right_child())
print(r.get_right_child().get_root_val())
r.get_right_child().set_root_val("hello")
print(r.get_right_child().get_root_val())