code: public FollowPlaylistRequest.Builder followPlaylist(String owner_id, String playlist_id, boolean public_) {
      return new FollowPlaylistRequest.Builder(accessToken)
              .setDefaults(httpManager, scheme, host, port)
              .owner_id(owner_id)
              .playlist_id(playlist_id)
              .public_(public_);
    }
docs: Add the current user as a follower of a playlist.
  
  @param owner_id    The Spotify user ID of the person who owns the playlist.
  @param playlist_id The Spotify ID of the playlist. Any playlist can be followed, regardless of its
  public/private status, as long as you know its playlist ID.
  @param public_     Default: true. If true the playlist will be included in user's public playlists, if false it
  will remain private. To be able to follow playlists privately, the user must have granted the
  playlist-modify-private scope.
  @return A {@link FollowPlaylistRequest.Builder}.
  @see <a href="https://developer.spotify.com/web-api/user-guide/#spotify-uris-and-ids">Spotify: URLs &amp; IDs</a>