Sets the text completer for this tag widget to the inputed completer.
        
        :param      completer | <QCompleter>

def setCompleter( self, completer ):
        """
        Sets the text completer for this tag widget to the inputed completer.
        
        :param      completer | <QCompleter>
        """
        if ( self._completer == completer ):
            return
        elif ( self._completer ):
            self._completer.activated.disconnect(self.finishEditing)
        
        self._completer = completer
        
        if ( completer ):
            completer.activated.connect(self.finishEditing)