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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def frame(self, frame_reference):
 """ Switches focus to the specified frame, by index, name, or webelement. :Args: - frame_reference: The name of the window to switch to, an integer representing the index, or a webelement that is an (i)frame to switch to. :Usage: :: driver.switch_to.frame('frame_name') driver.switch_to.frame(1) driver.switch_to.frame(driver.find_elements_by_tag_name("iframe")[0]) """

        if isinstance(frame_reference, basestring) and self._driver.w3c:
            try:
                frame_reference = self._driver.find_element(By.ID, frame_reference)
            except NoSuchElementException:
                try:
                    frame_reference = self._driver.find_element(By.NAME, frame_reference)
                except NoSuchElementException:
                    raise NoSuchFrameException(frame_reference)

        self._driver.execute(Command.SWITCH_TO_FRAME, {'id': frame_reference})