code: def children(self):
          
  
          if self.left and self.left.data is not None:
              yield self.left, 0
          if self.right and self.right.data is not None:
              yield self.right, 1
docs: Returns an iterator for the non-empty children of the Node
  
          The children are returned as (Node, pos) tuples where pos is 0 for the
          left subnode and 1 for the right.
  
          >>> len(list(create(dimensions=2).children))
          0
  
          >>> len(list(create([ (1, 2) ]).children))
          0
  
          >>> len(list(create([ (2, 2), (2, 1), (2, 3) ]).children))
          2