BST Sort

While playing with Binary Search Trees , you discover the following sorting algorithm. Given an unsorted array of $n$ distinct numbers, you begin by iterating through it and insert each value to a Binary Search Tree. You then call the recursive procedure shown below on the tree.

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def sort_tree(node):
    if node is not None:
        sort_tree(node.left)
        print node.value
        sort_tree(node.right)

It prints out the array in sorted order. What is the run-time of this sorting algorithm?