ESC180 - Node and Binary Search Tree Classes

class Node:
    def __init__(self, cargo = None, left = None, right = None):
        self.cargo = cargo
        self.left = left
        self.right = right

    def __str__(self):
        return str(self.cargo)

class BinarySearchTree:
    def __init__(self, root = None):
        self.root = root

    def insert(self, val):
        #if there is no root, create a Node at the root
        if self.root == None:
            self.root = Node(val)
        #if there is a root, check whether the value is greater than or less than the root
        #Check the appropriate left or right pointer to see if a Node exists, and continue evaluating
        #or assign to the left or right pointer when appropriate
        #else call Insert_Helper
        else:
            self.Insert_Helper(self.root, val)

    def Insert_Helper(self, current_node, val):
        #If the value is less than the current node's cargo
        if val < current_node.cargo:
            #if the current node's left is None
            if current_node.left == None:
                current_node.left = Node(val)
            else:
                self.Insert_Helper(current_node.left, val)
        elif val > current_node.cargo:
            #if the current node's right is None
            if current_node.right == None:
                #Create a node with that value
                current_node.right = Node(val)
            else:
                self.Insert_Helper(current_node.right, val)

    def search(self, val):
        search_t1 = perf_counter()
        result = self.search_helper(self.root, val)
        if result:
            search_t2 = perf_counter()
            time_elapsed = search_t2 - search_t1
            print('Elapsed time: ' + str(time_elapsed))
            return True
        else:
            search_t2 = perf_counter()
            time_elapsed = search_t2 - search_t1
            print('Elapsed time: ' + str(time_elapsed))
            return False

    def search_helper(self, current_node, val):
        #if the current node is empty, return False
        if current_node == None:
            return False
        #elif the current node is the value, return True
        elif current_node.cargo == val:
            return True
        elif val < current_node.cargo:
            self.search_helper(current_node.left, val)
        elif val > current_node.cargo:
            self.search_helper(current_node.right, val)