how to find post order traversal from inorder and preorder python code example

Example 1: traversing a tree in python

"""Inorder Traversing"""
def inorder_traversing(self, root):
  res = []
  if root:
    res = self.inorder_traversing(root.left)
    res.append(root.data)
    res = res + inorder_traversing(root.right)
   return res

Example 2: traversing a tree in python

"""Post-order"""
    def postorder_traversal(self, root):
        res = []

        if root:
            res = self.predorder_traversal(root.left)
            res = res + self.predorder_traversal(root.right)
            res.append(root.data)
        return res