code: func (p *pageMeta) Param(key interface{}) (interface{}, error) {
  	return resource.Param(p, p.s.Info.Params(), key)
  }
docs: // Param is a convenience method to do lookups in Page's and Site's Params map,
  // in that order.
  //
  // This method is also implemented on SiteInfo.
  // TODO(bep) interface