# File lib/main/mode.rb, line 22
      def find_by_mode m, options = {}
        quiet = options['quiet'] || options[:quiet]
        each_pair do |mode, klass|
          return mode if mode == m
        end
        candidates = []
        each_pair do |mode, klass|
          candidates << mode if mode.index(m) == 0
        end
        case candidates.size
          when 0
            nil
          when 1
            candidates.first
          else
            raise Ambiguous, "ambiguous mode: #{ m } = (#{ candidates.sort.join ' or ' })?"
        end
      end