what am I doing wrong?

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.TreeMap;
import java.util.Map;
import java.util.Arrays;
public class QuickFix {

  public void addForgottenVideo(Course course) {
    // TODO(1):  Create a new video called "The Beginning Bits"
Video video = new Video("The Beginning Bits");
    // TODO(2):  Add the newly created video to the course videos as the second video.
course.getVideos().add(1, video);
  }

  public void fixVideoTitle(Course course, String oldTitle, String newTitle) {
Map<String, Video> newVideoMap = videosbyTitle(course);
    if newVideoMap.containsKey(oldTitle) {
      newVideoMap.put(newTitle);
    newVideoMap.remove(oldTitle);
    }
    return newVideoMap;
  }

  public Map<String, Video> videosByTitle(Course course) {
   Map<String, Video> byTitle = new TreeMap<String, Video>();
    for(Video video : course.getVideos()) {
      byTitle.put(video.getTitle(), video);
    }
    return byTitle;
  }

}