old_contents: module.exports = class School {
  constructor(){
    this.grades = {}
  }
  roster(){
    return this.grades
  }
  add(name, grade){
    if(this.grades[grade]){
      this.grades[grade].push(name)
      this.grades[grade].sort()
    } else {
      this.grades[grade] = [name]
    }
  }
  grade(grade){
    return this.grades[grade]? this.grades[grade].sort() : []
  }
  
  }
  
  /*school.add('Blair',2)
  school.add('James',2)
  school.add('Paul',2)
  //let expectedDb = { 2 : [ 'Blair', 'James', 'Paul' ] }
  console.log(school.roster())*/
  
new_contents: module.exports = class School {
  constructor(){
    this.grades = {}
  }
  roster(){
    return this.grades;
  }
  add(name, grade){
    if(!this.grades[grade]){
      this.grades[grade] = [name]
    }else{
      this.grades[grade].push(name)
      this.grades[grade].sort()
    }
  }
  grade(number){
    const result = Object.keys(this.grades).filter(x => x== number).map(x => this.grades[x])
    const verific = (x=> x? x.sort(): [])
    let resp = verific(result[0]);
    return resp;
  }
  
  
  }
  
subject: Update grade-school.js