'Removes selection of checkbox identified by `locator`.
Does nothing if the checkbox is not checked. Key attributes for
checkboxes are `id` and `name`. See `introduction` for details about
locating elements.'

@keyword
def unselect_checkbox(self, locator):

    self.info(("Unselecting    checkbox    '%s'." % locator))
    element = self._get_checkbox(locator)
    if element.is_selected():
        element.click()
