code: def serialize_tree(tree, feature_names, outfile):
          
  
          tree_ = tree.tree_
          feature_name = [feature_names[i] if i != _tree.TREE_UNDEFINED else 'n/a' for i in tree_.feature]
  
          def traverse(node, depth, outfile):
              if tree_.feature[node] != _tree.TREE_UNDEFINED:
                  name = feature_name[node]
                  threshold = tree_.threshold[node]
  
                  # Define internal node for serialization
                  internal_node = {
                      'type': 'internal',
                      'split': {
                          'type': 'continuous',
                          'featureIndex': feature_names.index(name),
                          'threshold': threshold
                      }
                  }
  
                  # Serialize the internal Node
                  json.dump(internal_node, outfile)
                  outfile.write('\n')
  
                  # Traverse Left
                  traverse(tree_.children_left[node], depth + 1, outfile)
  
                  # Traverse Rigiht
                  traverse(tree_.children_right[node], depth + 1, outfile)
              else:
                  leaf_node = {
                      'type': 'leaf',
                      'values': tree_.value[node].tolist()[0]
                  }
  
                  # Serialize the leaf node
                  json.dump(leaf_node, outfile)
                  outfile.write('\n')
  
          traverse(0, 1, outfile)
docs: :type feature_names: list
          :type tree: sklearn.tree.tree.BaseDecisionTree
          :param tree: sklearn.tree.tree
          :param feature_names:
          :return: