code: def _check_normalization(self):
          
          lastDistance = None
          distance     = None
          for idx in xrange(len(self) - 1):
              distance = self[idx+1][0] - self[idx][0]
  
              # first run
              if lastDistance is None:
                  lastDistance = distance
                  continue
  
              if lastDistance != distance:
                  return False
  
              lastDistance = distance
  
          return True
docs: Checks, if the TimeSeries is normalized.
  
          :return:    Returns :py:const:`True` if all data entries of the TimeSeries have an equal temporal
              distance, :py:const:`False` otherwise.