# File lib/chef/shef/ext.rb, line 37
      def ensure_session_select_defined
        # irb breaks if you prematurely define IRB::JobMangager
        # so these methods need to be defined at the latest possible time.
        unless jobs.respond_to?(:select_session_by_context)
          def jobs.select_session_by_context(&block)
            @jobs.select { |job| block.call(job[1].context.main)}
          end
        end

        unless jobs.respond_to?(:session_select)
          def jobs.select_shef_session(target_context)
            session = if target_context.kind_of?(Class)
              select_session_by_context { |main| main.kind_of?(target_context) }
            else
              select_session_by_context { |main| main.equal?(target_context) }
            end
            Array(session.first)[1]
          end
        end
      end