docs: def itemFromTag( self, tag ):
          """
          Returns the item assigned to the given tag.
          
          :param      tag | <str>
          
          :return     <XMultiTagItem> || None
          """
          for row in range(self.count() - 1):
              item = self.item(row)
              if ( item and item.text() == tag ):
                  return item
          return None