title: Find GAE Datastore entities by application ID
body: <p>I transferred a bunch of entities from one application to another. For most of them, the "application" part of the entity key got successfully converted from <code>s~old-app</code> to <code>s~new-app</code>. However, there are some bad apples that didn't get converted, causing new-app to throw errors like <code>BadRequestError: app s~old-app cannot access app s~new-app's data</code>.</p>
  
  <p>How can I find these items and fix them?</p>