# File lib/symetrie_com/acts_as_better_nested_set.rb, line 423
        def set_left_right # already protected by a transaction within #create
          maxright = base_set_class.maximum(right_col_name, :conditions => scope_condition) || 0
          self[left_col_name] = maxright+1
          self[right_col_name] = maxright+2
        end