code: def get_daily_rates(date_req: datetime.datetime = None, lang: str = 'rus') -> Element:
      
      if lang not in ['rus', 'eng']:
          raise ValueError('"lang" must be string. "rus" or "eng"')
  
      base_url = const.CBRF_API_URLS['daily_rus'] if lang == 'rus' \
          else const.CBRF_API_URLS['daily_eng']
  
      url = base_url + 'date_req=' + utils.date_to_str(date_req) if date_req else base_url
  
      response = requests.get(url=url)
  
      return XML(response.text)
docs: Getting currency for current day.
  
      see example: http://www.cbr.ru/scripts/Root.asp?PrtId=SXML
  
      :param date_req:
      :type date_req: datetime.datetime
      :param lang: language of API response ('eng' || 'rus')
      :type lang: str
  
      :return: :class: `Element <Element 'ValCurs'>` object
      :rtype: ElementTree.Element