类型的字符串?'不符合协议'_CollectionType'

var desc = item.itemDescription
let regex:NSRegularExpression  = NSRegularExpression(
   pattern: "<.*?>",
   options: NSRegularExpressionOptions.CaseInsensitive,
   error: nil)!
let range = NSMakeRange(0, countElements(desc))
let htmlLessString :String = regex.stringByReplacingMatchesInString(desc,
   options: NSMatchingOptions.allZeros,
   range:range ,
   withTemplate: "")
var desc = item.itemDescription
let regex:NSReg