title: Get DI from within class in Phalcon
body: <p>How can I get the Service Locator (or the Dependency Object) from custom classes?</p>
  
  <p>I have:</p>
  
  <pre><code>class CustomerHelper extends Phalcon\Tag
  {
  
  }
  </code></pre>
  
  <p>and need to get the <code>flash</code> service for use in a custom function</p>