def slice(**options)
      defaults = {
        lower: nil,
        upper: nil,
        exclusive: false,
        lex: @lex
      }

      self.class::Slice.new(self, **defaults.merge(options))
    end
def slice(**options)
      defaults = {
        lower: nil,
        upper: nil,
        exclusive: false,
        lex: @lex
      }

      self.class::Slice.new(self, **defaults.merge(options))
    end
Returns a slice or partial selection of the set.
 @see Redstruct::SortedSet::Slice#initialize
 @return [Redstruct::SortedSet::Slice] a newly created slice for this set