code: def update_statistics(self, activityVectors):
          
          Y = activityVectors
          n = self.output_size
          A = np.zeros((n, n))
          batchSize = len(Y)
  
          for y in Y:
              active_units = np.where( y == 1 )[0]
              for i in active_units:
                  for j in active_units:
                      A[i,j] += 1.
  
          A = A/batchSize
          self.average_activity = self.exponential_moving_average(self.average_activity, A, self.smoothing_period)
docs: Updates the variable that maintains exponential moving averages of 
          individual and pairwise unit activiy