# File lib/rspec/core/metadata.rb, line 103
        def described_class
          container_stack.each do |g|
            return g[:describes]       if g.has_key?(:describes)
            return g[:described_class] if g.has_key?(:described_class)
          end

          container_stack.reverse.each do |g|
            candidate = g[:description_args].first
            return candidate unless String === candidate || Symbol === candidate
          end

          nil
        end