code: def numberOfDistalSegments(self, cells=None):
      
      if cells is None:
        cells = xrange(self.numberOfCells())
  
      n = 0
  
      for cell in cells:
        if self.internalDistalPermanences.nNonZerosOnRow(cell) > 0:
          n += 1
  
        for permanences in self.distalPermanences:
          if permanences.nNonZerosOnRow(cell) > 0:
            n += 1
  
      return n
docs: Returns the total number of distal segments for these cells.
  
      A segment "exists" if its row in the matrix has any permanence values > 0.
  
      Parameters:
      ----------------------------
      @param  cells (iterable)
              Indices of the cells