title: How can I get color properties of all actors?
body: <p>(This might be an easy question. However I don't know the solution.)</p>
  
  <p>I made an <strong>simple multi-STL files viewer</strong> using PyQt5 and VTK library.</p>
  
  <p>There is rendering widget (<code>QVTKRenderWindowInteractor</code>) and a reset button (<code>QPushButton</code>).</p>
  
  <p>If I click the reset button, the color of the actors (all loaded STL data) are changed to white. </p>
  
  <p>Following code is the reset button click function
  (It works well):</p>
  
  <pre><code>def _resetBtnClicked(self):
      # reset actor colors
      actorCollection = self.ren.GetActors()
      actorCollection.InitTraversal()
  
      cactor = actorCollection.GetNextActor() # first actor
      while cactor != actorCollection.GetLastActor():
          cactor.GetProperty().SetColor(1, 1, 1)
          cactor = actorCollection.GetNextActor()
      cactor.GetProperty().SetColor(1, 1, 1) # last actor
  </code></pre>
  
  <p>The self.ren is the  <code>vtk.vtkRenderer()</code> and I used while roop to deal with ACTORs COLOR using <code>.GetNextActor()</code>, sequently.</p>
  
  <p>However, I want to change the while loop  to a simple code, like <code>self.ren.GetActors().GetProperty().SetColor(1, 1, 1)</code> if possible (this '<code>self.ren.GetActors().GetProperty().SetColor(1, 1, 1)</code>' isn't existed). </p>
  
  <p>If there are several function I can use instead of while roop, please let me know.</p>