class Solution:
    def isSameTree(self, p: Optional[TreeNode], q: Optional[TreeNode]) -> bool:

        # base case: if both are null nodes
        if not p and not q:
            return True

        # if both happen to be actual nodes
        if p and q:
            return (p.val == q.val) and self.isSameTree(p.left, q.left) and self.isSameTree(p.right, q.right)

        # if either of them is not a null node
        return False