def model_query(model, session, args=None, **kwargs):
    """Query helper for db.sqlalchemy api methods.

    This accounts for `deleted` and `project_id` fields.

    :param model:        Model to query. Must be a subclass of ModelBase.
    :type model:         models.ModelBase

    :param session:      The session to use.
    :type session:       sqlalchemy.orm.session.Session

    :param args:         Arguments to query. If None - model is used.
    :type args:          tuple

    Keyword arguments:

    :keyword project_id: If present, allows filtering by project_id(s).
                         Can be either a project_id value, or an iterable of
                         project_id values, or None. If an iterable is passed,
                         only rows whose project_id column value is on the
                         `project_id` list will be returned. If None is passed,
                         only rows which are not bound to any project, will be
                         returned.
    :type project_id:    iterable,
                         model.__table__.columns.project_id.type,
                         None type

    :keyword deleted:    If present, allows filtering by deleted field.
                         If True is passed, only deleted entries will be
                         returned, if False - only existing entries.
    :type deleted:       bool


    Usage:

    .. code-block:: python

      from oslo_db.sqlalchemy import utils


      def get_instance_by_uuid(uuid):
          session = get_session()
          with session.begin()
              return (utils.model_query(models.Instance, session=session)
                           .filter(models.Instance.uuid == uuid)
                           .first())

      def get_nodes_stat():
          data = (Node.id, Node.cpu, Node.ram, Node.hdd)

          session = get_session()
          with session.begin()
              return utils.model_query(Node, session=session, args=data).all()

    Also you can create your own helper, based on ``utils.model_query()``.
    For example, it can be useful if you plan to use ``project_id`` and
    ``deleted`` parameters from project's ``context``

    .. code-block:: python

      from oslo_db.sqlalchemy import utils


      def _model_query(context, model, session=None, args=None,
                       project_id=None, project_only=False,
                       read_deleted=None):

          # We suppose, that functions ``_get_project_id()`` and
          # ``_get_deleted()`` should handle passed parameters and
          # context object (for example, decide, if we need to restrict a user
          # to query his own entries by project_id or only allow admin to read
          # deleted entries). For return values, we expect to get
          # ``project_id`` and ``deleted``, which are suitable for the
          # ``model_query()`` signature.
          kwargs = {}
          if project_id is not None:
              kwargs['project_id'] = _get_project_id(context, project_id,
                                                     project_only)
          if read_deleted is not None:
              kwargs['deleted'] = _get_deleted_dict(context, read_deleted)
          session = session or get_session()

          with session.begin():
              return utils.model_query(model, session=session,
                                       args=args, **kwargs)

      def get_instance_by_uuid(context, uuid):
          return (_model_query(context, models.Instance, read_deleted='yes')
                        .filter(models.Instance.uuid == uuid)
                        .first())

      def get_nodes_data(context, project_id, project_only='allow_none'):
          data = (Node.id, Node.cpu, Node.ram, Node.hdd)

          return (_model_query(context, Node, args=data, project_id=project_id,
                               project_only=project_only)
                        .all())

    """

    if not issubclass(model, models.ModelBase):
        raise TypeError(_("model should be a subclass of ModelBase"))

    query = session.query(model) if not args else session.query(*args)
    if 'deleted' in kwargs:
        query = _read_deleted_filter(query, model, kwargs['deleted'])
    if kwargs in 'project_id':
        query = _project_filter(query, model, kwargs['project_id'])

    return query
dataset/ETHPy150Open openstack/oslo.db/oslo_db/sqlalchemy/utils.py/model_query/swapped operands of `in`