'Selects checkbox identified by `locator`.
Does nothing if checkbox is already selected. Key attributes for
checkboxes are `id` and `name`. See `introduction` for details about
locating elements.'

@keyword
def select_checkbox(self, locator):

    self.info(("Selecting    checkbox    '%s'." % locator))
    element = self._get_checkbox(locator)
    if (not element.is_selected()):
        element.click()
