code: def do_heavy_work(self, block):
          
          cipher_key = self.gen_key(32)
          in_file_path = block.latest_file_info.path
          dst_file_path = block.processed_data_file_info.path + self.get_extension()
          self.log.debug("Encrypting file '%s' with key '%s' to file '%s'",
                         in_file_path, cipher_key, dst_file_path)
          self.encrypt_file(key=cipher_key,
                            in_filename=in_file_path,
                            out_filename=dst_file_path)
          block.cipher_key = cipher_key
          block.ciphered_file_info = FileInfo(dst_file_path)
          block.latest_file_info = block.ciphered_file_info
          return block
docs: Expects Compressor Block like objects