Make TreeMap with Multiple Keys

package com.example.model;

import java.util.List;

public class Course {
  private String mName;
  private List<Video> mVideos; 

  public Course(String name, List<Video> videos) {
    mName = name;
    mVideos = videos;
  }

  public String getName() {
    return mName;
  }

  public List<Video> getVideos() {
    return mVideos;
  }

}

package com.example.model;

public class Video {
  private String mTitle;

  public Video(String title) {
    mTitle = title;
  }

  public String getTitle() {
    return mTitle;
  }

  public void setTitle(String title) {
    mTitle = title;
  }

}

import com.example.model.Course;
import com.example.model.Video;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;

public class QuickFix {

  public void addForgottenVideo(Course course) {
    Video video = new Video("The Beginning Bits");
    List<Video> videoList = course.getVideos();
    videoList.add(video);
    videoList.set(1,video);

    // TODO(1):  Create a new video called "The Beginning Bits"

    // TODO(2):  Add the newly created video to the course videos as the second video.

  }

  public void fixVideoTitle(Course course, String oldTitle, String newTitle) {

  }

  public Map<String, Video> videosByTitle(Course course) {
    Map<String,Video> videosByTitle = new TreeMap<>();
    List<Video> videoList = course.getVideos();
    for(Video video : videoList) {
      String title = video.getTitle();      
      //List<Video> videos = videosByTitle.get(title);
     // titles.add(video.getTitle());
      //if(videos == null){
      //  videos = new ArrayList<>();
      //  videos.add(video);
      //}
      videosByTitle.put(title,video);  
    }

    return videosByTitle;

  }

}