ImageFileWriter requires an image as an input, not a filter

[Mario Ceresa]

Currently the pipeline connects all the filters with the pattern:

fil2.SetInput(fil1)

Nevertheless it doesn't work for ImageFileWriter:

In [1]: import itk
In [2]: reader = itk.ImageFileReader.ISS3.New()
In [3]: writer = itk.ImageFileWriter.ISS3.New()
In [4]: writer.SetInput(reader)
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)

titk/src/titk/<ipython console> in <module>()

TypeError: in method 'itkImageFileWriterISS3_SetInput', argument 2 of type 'itkImageSS3 const *'