How to use the motor.MotorGridOut function in motor

def test_write_file_like(self):
        one = motor.MotorGridIn(self.db.fs)
        yield one.write(b"hello world")
        yield one.close()

        two = motor.MotorGridOut(self.db.fs, one._id)
        three = motor.MotorGridIn(self.db.fs)
        yield three.write(two)
        yield three.close()

        four = motor.MotorGridOut(self.db.fs, three._id)
        self.assertEqual(b"hello world", (yield four.read()))

def test_attributes(self):
        f = motor.MotorGridIn(
            self.db.fs,
            filename="test",
            foo="bar",
            content_type="text")

        yield f.close()

        g = motor.MotorGridOut(self.db.fs, f._id)
        attr_names = (
            '_id',
            'filename',
            'name',
            'name',
            'content_type',
            'length',
            'chunk_size',
            'upload_date',
            'aliases',
            'metadata',
            'md5')

        for attr_name in attr_names:
            self.assertRaises(InvalidOperation, getattr, g, attr_name)

def test_grid_out_file_document(self):
        one = motor.MotorGridIn(self.db.fs)
        yield one.write(b"foo bar")
        yield one.close()

        file_document = yield self.db.fs.files.find_one()
        two = motor.MotorGridOut(
            self.db.fs, file_document=file_document)

        self.assertEqual(b"foo bar", (yield two.read()))

        file_document = yield self.db.fs.files.find_one()
        three = motor.MotorGridOut(self.db.fs, 5, file_document)
        self.assertEqual(b"foo bar", (yield three.read()))

        gridout = motor.MotorGridOut(self.db.fs, file_document={})
        with self.assertRaises(NoFile):
            yield gridout.open()

def test_grid_out_default_opts(self):
        self.assertRaises(TypeError, motor.MotorGridOut, "foo")
        gout = motor.MotorGridOut(self.db.fs, 5)
        with self.assertRaises(NoFile):
            yield gout.open()

        a = motor.MotorGridIn(self.db.fs)
        yield a.close()

        b = yield motor.MotorGridOut(self.db.fs, a._id).open()

        self.assertEqual(a._id, b._id)
        self.assertEqual(0, b.length)
        self.assertEqual(None, b.content_type)
        self.assertEqual(255 * 1024, b.chunk_size)
        self.assertTrue(isinstance(b.upload_date, datetime.datetime))
        self.assertEqual(None, b.aliases)
        self.assertEqual(None, b.metadata)
        self.assertEqual("d41d8cd98f00b204e9800998ecf8427e", b.md5)

def test_grid_out_custom_opts(self):
        one = motor.MotorGridIn(
            self.db.fs, _id=5, filename="my_file",
            contentType="text/html", chunkSize=1000, aliases=["foo"],
            metadata={"foo": 1, "bar": 2}, bar=3, baz="hello")

        yield one.write(b"hello world")
        yield one.close()

        two = yield motor.MotorGridOut(self.db.fs, 5).open()

        self.assertEqual(5, two._id)
        self.assertEqual(11, two.length)
        self.assertEqual("text/html", two.content_type)
        self.assertEqual(1000, two.chunk_size)
        self.assertTrue(isinstance(two.upload_date, datetime.datetime))
        self.assertEqual(["foo"], two.aliases)
        self.assertEqual({"foo": 1, "bar": 2}, two.metadata)
        self.assertEqual(3, two.bar)
        self.assertEqual("5eb63bbbe01eeed093cb22bb8f5acdc3", two.md5)

def test_gridout_open_exc_info(self):
        if sys.version_info < (3, ):
            raise SkipTest("Requires Python 3")

        g = motor.MotorGridOut(self.db.fs, "_id that doesn't exist")
        try:
            yield g.open()
        except NoFile:
            _, _, tb = sys.exc_info()

            # The call tree should include PyMongo code we ran on a thread.
            formatted = '\n'.join(traceback.format_tb(tb))
            self.assertTrue('_ensure_file' in formatted)

def test_grid_out_file_document(self):
        one = motor.MotorGridIn(self.db.fs)
        yield one.write(b"foo bar")
        yield one.close()

        file_document = yield self.db.fs.files.find_one()
        two = motor.MotorGridOut(
            self.db.fs, file_document=file_document)

        self.assertEqual(b"foo bar", (yield two.read()))

        file_document = yield self.db.fs.files.find_one()
        three = motor.MotorGridOut(self.db.fs, 5, file_document)
        self.assertEqual(b"foo bar", (yield three.read()))

        gridout = motor.MotorGridOut(self.db.fs, file_document={})
        with self.assertRaises(NoFile):
            yield gridout.open()

def test_grid_out_default_opts(self):
        self.assertRaises(TypeError, motor.MotorGridOut, "foo")
        gout = motor.MotorGridOut(self.db.fs, 5)
        with self.assertRaises(NoFile):
            yield gout.open()

        a = motor.MotorGridIn(self.db.fs)
        yield a.close()

        b = yield motor.MotorGridOut(self.db.fs, a._id).open()

        self.assertEqual(a._id, b._id)
        self.assertEqual(0, b.length)
        self.assertEqual(None, b.content_type)
        self.assertEqual(255 * 1024, b.chunk_size)
        self.assertTrue(isinstance(b.upload_date, datetime.datetime))
        self.assertEqual(None, b.aliases)
        self.assertEqual(None, b.metadata)
        self.assertEqual("d41d8cd98f00b204e9800998ecf8427e", b.md5)

# Send the initial aggregate as PyMongo expects.
            motor_obj._lazy_init()
            return ChangeStream(motor_obj)
        if isinstance(motor_obj, motor.motor_tornado.MotorLatentCommandCursor):
            return CommandCursor(motor_obj)
        if isinstance(motor_obj, motor.motor_tornado.MotorCommandCursor):
            return CommandCursor(motor_obj)
        if isinstance(motor_obj, _MotorRawBatchCommandCursor):
            return CommandCursor(motor_obj)
        if isinstance(motor_obj, motor.motor_tornado.MotorCursor):
            return Cursor(motor_obj)
        if isinstance(motor_obj, _MotorRawBatchCursor):
            return Cursor(motor_obj)
        if isinstance(motor_obj, motor.MotorGridIn):
            return GridIn(None, delegate=motor_obj)
        if isinstance(motor_obj, motor.MotorGridOut):
            return GridOut(None, delegate=motor_obj)
        if isinstance(motor_obj, motor.motor_tornado.MotorGridOutCursor):
            return GridOutCursor(motor_obj)
        else:
            return motor_obj