docs: def decrypt(self, key, flags=0):
          """
          Decrypts encrypted data message
          @param key - symmetic key to decrypt
          @param flags - OR-ed combination of Flags constant
          """
          bio = Membio()
          if libcrypto.CMS_EncryptedData_decrypt(self.ptr, key, len(key), None,
                                                 bio.bio, flags) <= 0:
              raise CMSError("decrypt data")
          return str(bio)