title: How to use SimpleITK.WarpImageFilter function in python
body: <h1>I can't find any python documentation on this function.</h1>
  <p>I tried the following code, but the output is absolutely wrong.</p>
  <pre><code>warp = sitk.WarpImageFilter()
  warp.SetInterpolator(sitk.sitkLinear)
  out = warp.Execute(reference_img, transform_img)
  </code></pre>
  <p>it gives me exactly the reference_img, but not the transformed image.</p>
  <p>Have you ever used this function? Could you please help me on this issue?</p>