You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: external_entry.rb
    path of file: ./repos/bootcamp/app/models
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

class ExternalEntry < ApplicationRecord
  include ActionView::Helpers::AssetUrlHelper

  belongs_to :user

  validates :title, presence: true
  validates :url, presence: true
  validates :published_at, presence: true

  def thumb
    
    def save_rdf_feed(user, rdf_item, feed_updated)
      return if ExternalEntry.find_by(url: rdf_item.link)

      published_at = rdf_publish_date(rdf_item, feed_updated)
      ExternalEntry.create(
        title: rdf_item.title,
        url: rdf_item.link,
        summary: rdf_item.description,
        thumbnail_image_url: nil,
        published_at: published_at.utc? ? Time.zone.parse(published_at.to_s) : published_at,
        user:
      )
    end