PbootCms导航判断是否有二级菜单

PbootCms导航如何判断是否有二级菜单
{pboot:nav num=15 parent=0}
[nav:name]
  {pboot:if([nav:soncount]>0)}
  {else}
  {/pboot:if} 
  {pboot:2nav num=10 parent=[nav:scode]}
    [2nav:name]
  {/pboot:2nav}
{/pboot:nav}