code: def getContGroupArrays(arrays, groupPositions, arrayKeys=None):
      
      if arrayKeys is None:
          arrayKeys = list(viewkeys(arrays))
      matchingArrays = dict()
      for key in arrayKeys:
          matchingArrays[key] = arrays[key][groupPositions]
      return matchingArrays
docs: Convinience function to generate a subset of arrays from specified array
      positions.
  
      :param arrays: a dictionary containing ``numpy.arrays``
      :param groupPositions: arrays positions that should be included in the
          subset of arrays
      :param arrayKeys: a list of "arrays" keys that should be included in the
          subset of arrays, if None all keys are selected
  
      :returns: a dictionary containing ``numpy.arrays``