docs: def download(cls, url=None, force_download=False):
          """Downloads uniprot_sprot.xml.gz and reldate.txt (release date information) from URL or file path
  
          .. note::
  
              only URL/path of xml.gz is needed and valid value for parameter url. URL/path for reldate.txt have to be the
              same folder
      
          :param str url: UniProt gzipped URL or file path
          :param force_download: force method to download
          :type force_download: bool
          """
          if url:
              version_url = os.path.join(os.path.dirname(url), defaults.VERSION_FILE_NAME)
          else:
              url = os.path.join(defaults.XML_DIR_NAME, defaults.SWISSPROT_FILE_NAME)
              version_url = os.path.join(defaults.XML_DIR_NAME, defaults.VERSION_FILE_NAME)
  
          xml_file_path = cls.get_path_to_file_from_url(url)
          version_file_path = cls.get_path_to_file_from_url(version_url)
  
          if force_download or not os.path.exists(xml_file_path):
  
              log.info('download {} and {}'.format(xml_file_path, version_file_path))
  
              scheme = urlsplit(url).scheme
  
              if scheme in ('ftp', 'http'):
                  urlretrieve(version_url, version_file_path)
                  urlretrieve(url, xml_file_path)
  
              elif not scheme and os.path.isfile(url):
                  shutil.copyfile(url, xml_file_path)
                  shutil.copyfile(version_url, version_file_path)
  
          return xml_file_path, version_file_path