Change MR-level allowed approvers and approver groups.

        Args:
            approver_ids (list): User IDs that can approve MRs
            approver_group_ids (list): Group IDs whose members can approve MRs

        Raises:
            GitlabAuthenticationError: If authentication is not correct
            GitlabUpdateError: If the server failed to perform the request

def set_approvers(self, approver_ids=[], approver_group_ids=[], **kwargs):
        """Change MR-level allowed approvers and approver groups.

        Args:
            approver_ids (list): User IDs that can approve MRs
            approver_group_ids (list): Group IDs whose members can approve MRs

        Raises:
            GitlabAuthenticationError: If authentication is not correct
            GitlabUpdateError: If the server failed to perform the request
        """
        path = '%s/%s/approvers' % (self._parent.manager.path,
                                    self._parent.get_id())
        data = {'approver_ids': approver_ids,
                'approver_group_ids': approver_group_ids}
        self.gitlab.http_put(path, post_data=data, **kwargs)