check_bt_is_subtree_of_another_bt.py

class Node():

    def __init__(self, val):
        self.val = val
        self.left = None
        self.right = None


def check(root1, root2):
    if root1 == None:
        return True
    if root2 == None:
        return False
    if are_identical(root1, root2):
        return True
    return (check(root1.left, root2) or check(root1.right, root2))


def are_identical(root1, root2):
    if root1 == None and root2 == None:
        return True
    if root1 == None or root2 == None:
        return False
    return (root1.val == root2.val and are_identical(root1.left, root2.left) and are_identical(root1.right, root2.right))