title: Google Pub/Sub pull Error parsing subscription resource is not specified
body: <p>I Using the Google Console to set up Pub/Sub and implemented asynchronous pull to get the message from the subscription. This is the command line with the error message saying Error paring the subscription. With the error message, how can I find the project info and set the attribute [property] correctly?</p>
  
  <pre><code>C:\Program Files (x86)\Google\Cloud SDK&gt;gcloud beta pubsub subscriptions pull GmailSub
  </code></pre>
  
  <blockquote>
    <p>ERROR: (gcloud.beta.pubsub.subscriptions.pull) Error parsing
    [subscription]. The [subscription] resource is not properly specified.</p>
    
    <p>Failed to find attribute [project]. The attribute can be set in the following ways: - Set the property <code>[core/project]</code> or provide the flag <code>[--project]</code> on the command line</p>
  </blockquote>