title: How to delete a property/value from an entity using google cloud datastore
body: <p>I am learning <code>google.cloud.datastore</code>, and like to know how to delete a property along with its value from an <code>entity</code>. Also, is it possible to delete a specific or a list of properties from all entities of a certain <code>kind</code>?</p>
  
  <p>My understanding is <code>datastore</code> stores/manipulates data in a row-wise way (<code>entities</code>)?</p>
  
  <p>cheers</p>