title: Integrate Variables using Paraview Python Shell
body: <p>I want to access to the result of U using Python Shell after applying integrate variables filter. This is easy to be done manually but I want to do this using Python Shell as my further calculations require me to do some math.</p>
  
  <p>To use Python Shell, I open Paraview and select my mesh regions and cell arrays. I press apply and after that, I run Python Shell and run my script. However, I get error as: </p>
  
  <pre><code>Traceback (most recent call last):
  File "&lt;string&gt;", line 16, in &lt;module&gt; 
  AttributeError: 'NoneType' object has no attribute 'GetValue'
  </code></pre>
  
  <p>This is the script that I am using:</p>
  
  <pre><code>import paraview.simple as pvs
  data = pvs.Wavelet()
  my_slice = pvs.Slice(Input=data)
  my_slice.SliceType = 'Plane'
  my_slice.SliceType.Origin = [0.0, 0.0, 0.0]
  my_slice.SliceType.Normal = [0.0, 1.0, 0.0]
  my_slice.SliceType.Offset = 0.0
  my_slice.Crinkleslice = 0
  my_slice.Triangulatetheslice = 0
  my_slice.SliceOffsetValues = [0.0]
  iv = IntegrateVariables(Input=my_slice)
  iv.UpdatePipeline()
  data = servermanager.Fetch(iv) 
  numPoints=data.GetNumberOfCells()
  print numPoints
  U10=data.GetCellData().GetArray("U1").GetValue(1) # This is the line no. 16
  print U10
  </code></pre>
  
  <p>I am doing something wrong. I checked Google to get some advice but I couldn't find my mistake. Can you help me to correct this? Thank you.</p>
  
  <p><strong>Edit for the solution:</strong></p>
  
  <p>I solved my problem and updated my code little bit. I wanted to edit my question for future-readers. The following code worked for me:</p>
  
  <pre><code>from paraview.simple import *
  disp1OpenFOAM = FindSource('disp1.OpenFOAM')
  slice1 = Slice(Input=disp1.OpenFOAM)
  slice1.SliceType = 'Plane'
  slice1.Crinkleslice = 0
  slice1. Triangulatetheslice = 1
  slice1.SliceOffsetValues = [0.0]
  slice1.SliceType.Origin [0.0, 0.0023, 0.00]
  slice1.SliceType.Normal [0.0, 1.0, 0.0]
  integrateVariables1 = integrateVariables(Input=slice1)
  DataSliceFile = paraview.servermanager.Fetch(integrateVariables1)
  numCells = DataSliceFile.GetNumberOfCells()
  U1 = [ ]
  for x in range(numCells):
  U1.append(DataSliceFile.GetCellData().GetArray('U1').GetValue(x))
  print U1
  </code></pre>