code: def frame(self, frame_reference):
          
          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})
docs: 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])