Mongoose.js - TypeError: Model.deleteOne不是函数

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

// 定义一个Schema
const userSchema = new Schema({
  name: String,
  age: Number
});

// 定义一个Model
const User = mongoose.model('User', userSchema);

// 连接MongoDB数据库
mongoose.connect('mongodb://localhost/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true })
  .then(() => {
    console.log('Connected to MongoDB');
    
    // 使用deleteOne方法删除文档
    User.deleteOne({ name: 'John' })
      .then(() => {
        console.log('Document deleted successfully');
      })
      .catch((error) => {
        console.error('Error deleting document:', error);
      })
      .finally(() => {
        // 关闭数据库连接
        mongoose.disconnect();
      });
  })
  .catch((error) => {
    console.error('Error connecting to MongoDB:', error);
  });