code: def get_file(self):
          
          if self.cdn_file_hashes:
              cdn_hash = self.cdn_file_hashes.pop(0)
              cdn_file = self.client(GetCdnFileRequest(
                  self.file_token, cdn_hash.offset, cdn_hash.limit
              ))
              cdn_file.bytes = self.cdn_aes.encrypt(cdn_file.bytes)
              self.check(cdn_file.bytes, cdn_hash)
          else:
              cdn_file = CdnFile(bytes(0))
  
          return cdn_file
docs: Calls GetCdnFileRequest and decrypts its bytes.
          Also ensures that the file hasn't been tampered.
  
          :return: the CdnFile result.