code: def assign_available_account_entitlement(self, user_id, dont_notify_user=None, origin=None):
          
          query_parameters = {}
          if user_id is not None:
              query_parameters['userId'] = self._serialize.query('user_id', user_id, 'str')
          if dont_notify_user is not None:
              query_parameters['dontNotifyUser'] = self._serialize.query('dont_notify_user', dont_notify_user, 'bool')
          if origin is not None:
              query_parameters['origin'] = self._serialize.query('origin', origin, 'str')
          response = self._send(http_method='POST',
                                location_id='c01e9fd5-0d8c-4d5e-9a68-734bd8da6a38',
                                version='5.0-preview.1',
                                query_parameters=query_parameters)
          return self._deserialize('AccountEntitlement', response)
docs: AssignAvailableAccountEntitlement.
          [Preview API] Assign an available entitilement to a user
          :param str user_id: The user to which to assign the entitilement
          :param bool dont_notify_user:
          :param str origin:
          :rtype: :class:`<AccountEntitlement> <azure.devops.v5_0.licensing.models.AccountEntitlement>`