# File lib/rspec/matchers/pretty.rb, line 8
      def to_sentence(words)
        return "" unless words
        words = Array(words).map { |w| to_word(w) }
        case words.length
          when 0
            ""
          when 1
            " #{words[0]}"
          when 2
            " #{words[0]} and #{words[1]}"
          else
            " #{words[0...-1].join(', ')}, and #{words[-1]}"
        end
      end