TTStyledText textFromXHTML不支持下划线标签吗？

NSString* htmlTitle = [NSString stringWithFormat:@\"UnderlinedBoldNormal\", we.title]; 
self.ttTitlelabel.text = [TTStyledText textFromXH`TML:htmlTitle];

TTStyledText

- (TTStyle*)underlineStyle
{
  //custom TTStyle implementation
} 

NSString* htmlTitle = [NSString stringWithFormat:@\"<span class=\\\"underlineStyle\\\">%@</span>\", we.title]; 
self.ttTitlelabel.text = [TTStyledText textFromXHTML:htmlTitle];