code: def set_password(self, service, username, password):
          
          service = self._safe_string(service)
          username = self._safe_string(username)
          password = self._safe_string(password)
          attrs = GnomeKeyring.Attribute.list_new()
          GnomeKeyring.Attribute.list_append_string(attrs, 'username', username)
          GnomeKeyring.Attribute.list_append_string(attrs, 'service', service)
          GnomeKeyring.Attribute.list_append_string(
              attrs, 'application', 'python-keyring')
          result = GnomeKeyring.item_create_sync(
              self.keyring_name, GnomeKeyring.ItemType.NETWORK_PASSWORD,
              "Password for '%s' on '%s'" % (username, service),
              attrs, password, True)[0]
          if result == GnomeKeyring.Result.CANCELLED:
              # The user pressed "Cancel" when prompted to unlock their keyring.
              raise PasswordSetError("Cancelled by user")
          elif result != GnomeKeyring.Result.OK:
              raise PasswordSetError(result.value_name)
docs: Set password for the username of the service