# File lib/vagrant-libvirt/action/prune_nfs_exports.rb, line 10
        def call(env)
          if env[:host]
            uuid = env[:machine].id
            # get all uuids
            uuids = env[:machine].provider.driver.connection.servers.all.map(&:id)
            # not exiisted in array will removed from nfs
            uuids.delete(uuid)
            env[:host].capability(
              :nfs_prune, env[:machine].ui, uuids
            )
          end

          @app.call(env)
        end