title: parallelizing tasks in Luigi Orchestrator
body: <p>I defined three tasks <code>T1</code>, <code>T2</code>, and <code>T3</code>, and then a task <code>T4</code> as follows:</p>
  
  <pre><code>class T4(luigi.Task)
      def requires(self):
          return [T1(), T2(), T3()]
  </code></pre>
  
  <p>Is there a natural way to tell Luigi that I want these tasks <code>T1</code>, <code>T2</code>, and <code>T3</code> to be executed in parallel?</p>