How do I go about the traversal of Binary Search Trees?

Question

I'm trying to print out data by traversing through my Binary Search Tree with both Pre Order Traversal and In Order Traversal.

#Pre-Order Traversal
    def preTraverse(node):
        if(node != null):
            print(node)
            preTraverse(node.left)
            preTraverse(node.right)

    #In-Order Traversal
    def inTraverse(node):
        if(node != null):
            inTraverse(node.left)
            print(node)
            inTraverse(node.right)

I'm not quite sure if my logic is correct. What would I do if my node is null? Here is my code below(assuming my node class is correct):