push_workspace

# File lib/irb/ext/workspaces.rb, line 34
    def push_workspace(*_main)
      if _main.empty?
        if workspaces.empty?
          print "No other workspace\n"
          return nil
        end
        ws = workspaces.pop
        workspaces.push @workspace
        @workspace = ws
        return workspaces
      end

      workspaces.push @workspace
      @workspace = WorkSpace.new(@workspace.binding, _main[0])
      if !(class<<main;ancestors;end).include?(ExtendCommandBundle)
        main.extend ExtendCommandBundle
      end
    end