def multi_click(self, locator, params=None, timeout=None):
        """
        Presses left control or command button depending on OS, clicks and then releases control or command key.

        :param locator: locator tuple or WebElement instance
        :param params: (optional) locator parameters
        :param timeout: (optional) time to wait for element
        :return: None
        """
        platform = self.execute_script('return navigator.platform')
        multi_key = Keys.COMMAND if 'mac' in platform.lower() else Keys.LEFT_CONTROL
        self._click(locator, params, timeout, multi_key)