title: Update a property value without adding an additional value, in gremlin_python
body: <p>In the <a href="https://docs.aws.amazon.com/neptune/latest/userguide/access-graph-gremlin-differences.html" rel="nofollow noreferrer">docs</a> under <strong>Updating a Vertex Property</strong>, it is mentioned that one can <em>"update a property value without adding an additional value to the set of values"</em>
  by doing<br>
  <code>g.V('exampleid01').property(single, 'age', 25)</code>  </p>
  
  <p>In <strong>gremlin_python</strong>, I am unable to run a query like the above.<br>
  I get the error:  </p>
  
  <pre><code>update_prop_overwrite = g.V().hasLabel('placeholder-vertex').property(single,'maker','unknown').next()
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  NameError: name 'single' is not defined 
  </code></pre>
  
  <p>How can I resolve this so that I can replace a Vertex property value in Neptune?<br>
  Without <code>single</code> the query will append the new property value to the property key if a value exists already.  </p>