code: def addTag( self, tag ):
          
          if ( not (tag and self.isTagValid(tag)) ):
              return False
          
          self.blockSignals(True)
          create_item = self.createItem()
          if create_item:
              self.insertItem(self.row(create_item), XMultiTagItem(tag, self))
              create_item.setText('')
          else:
              self.addItem(XMultiTagItem(tag, self))
          self.blockSignals(False)
          
          if ( not self.signalsBlocked() ):
              self.tagCreated.emit(tag)
          
          return False
docs: Adds a new tag to the edit.
          
          :param      tag | <str>
          
          :return     <bool>