如果我有两个模式：我该如何将这两者联系起来，
我收到此错误

throw new TypeError('Router.use() requires a middleware function but got a ' + gettype(fn))
      ^

TypeError: Router.use() requires a middleware function but got a Object

我的档案
faculty.js

const mongoose = require("mongoose");

const facultySchema = new mongoose.Schema({
    facultyCode: {
        type: String,
        required: true,
        unique: true
      },
      facultyName: {
        type: String,
        required: true,
        unique: true
      }
});

module.exports = mongoose.model("Faculty", facultySchema);

departmentSchema.js

const mongoose = require("mongoose");

const Schema = mongoose.Schema;

const departmentSchema = new mongoose.Schema({
    departmentName: {
        type: String,
        required: true,
        unique: true
      },
      departmentCode: {
        type: String,
        required: true,
        unique: true
      },
      facultyId: {
        type: Schema.Types.ObjectId,
        required: true,
        ref: 'facultySchema'
      }
});

module.exports = mongoose.model("Department", departmentSchema);

错误代码形式vsCode

C:\Users\User\Documents\00-System\Backend\node_modules\express\lib\router\index.js:458
      throw new TypeError('Router.use() requires a middleware function but got a ' + gettype(fn))
      ^

TypeError: Router.use() requires a middleware function but got a Object
    at Function.use (C:\Users\User\Documents\00-System\Backend\node_modules\express\lib\router\index.js:458:13)
    at Function.<anonymous> (C:\Users\User\Documents\00-System\Backend\node_modules\express\lib\application.js:220:21)
    at Array.forEach (<anonymous>)
    at Function.use (C:\Users\User\Documents\00-System\Backend\node_modules\express\lib\application.js:217:7)
C:\Users\User\Documents\00-System\Backend\nod