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, obj):
		self.key = obj
	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())
