def to_s
      s = "#{@node_address}:[#{@blob_address}, #{@size}]"
      if @parent
        begin
          s += " ^#{@parent.node_address}"
        rescue
          s += ' ^@'
        end
      end
      if @smaller
        begin
          s += " <#{@smaller.node_address}"
        rescue
          s += ' <@'
        end
      end
      if @equal
        begin
          s += " =#{@equal.node_address}"
        rescue
          s += ' =@'
        end
      end
      if @larger
        begin
          s += " >#{@larger.node_address}"
        rescue
          s += ' >@'
        end
      end

      s
    end
def to_s
      s = "#{@node_address}:[#{@blob_address}, #{@size}]"
      if @parent
        begin
          s += " ^#{@parent.node_address}"
        rescue
          s += ' ^@'
        end
      end
      if @smaller
        begin
          s += " <#{@smaller.node_address}"
        rescue
          s += ' <@'
        end
      end
      if @equal
        begin
          s += " =#{@equal.node_address}"
        rescue
          s += ' =@'
        end
      end
      if @larger
        begin
          s += " >#{@larger.node_address}"
        rescue
          s += ' >@'
        end
      end

      s
    end
Textual version of the node data. It has the form
 node_address:[blob_address, size] ^parent_node_address
 <smaller_node_address >larger_node_address
 @return [String]