def addButton(self, button, alignment=None):
        """
        Adds a button the edit.  All the buttons will be layed out at the \
        end of the widget.
        
        :param      button      | <QToolButton>
                    alignment   | <Qt.Alignment>
        
        :return     <bool> | success
        """
        if alignment == None:
            if button.pos().x() < self.pos().x():
                alignment = Qt.AlignLeft
            else:
                alignment = Qt.AlignRight
        
        all_buttons = self.buttons()
        if button in all_buttons:
            return False
        
        # move the button to this edit
        button.setParent(self)
        button.setAutoRaise(True)
        button.setIconSize(self.iconSize())
        button.setCursor(Qt.ArrowCursor)
        button.setFixedSize(QSize(self.height() - 2, self.height() - 2))
        
        self._buttons.setdefault(alignment, [])
        self._buttons[alignment].append(button)
        self.adjustButtons()
        return True