new_contents: class Solution:
      def inorderTraversal(self, root):
          """
          :type root: TreeNode
          :rtype: List[int]
          """
          if root is None:
              return []
          else:
              return list(self.inorderTraversalGen(root))
  
      def inorderTraversalGen(self, node):
          if node.left is not None:
              for other in self.inorderTraversal(node.left):
                  yield other
          yield node.value
          if node.right is not None:
              for other in self.inorderTraversal(node.right):
                  yield other
              
  
  
subject: Add binary tree inorder traversal