How to use the fakeredis.to_bytes function in fakeredis

def test_pipeline_succeeds_despite_unwatched_key_changed(self):
        # Same setup as before except for the params to the WATCH command.
        self.redis.set('foo', 'bar')
        self.redis.rpush('greet', 'hello')
        p = self.redis.pipeline()
        try:
            # Only watch one of the 2 keys.
            p.watch('foo')
            nextf = fakeredis.to_bytes(p.get('foo')) + b'baz'
            # Simulate change happening on another thread.
            self.redis.rpush('greet', 'world')
            p.multi()
            p.set('foo', nextf)
            p.execute()

            # Check the commands were executed.
            self.assertEqual(self.redis.get('foo'), b'barbaz')
        finally:
            p.reset()

def test_pipeline_succeeds_when_watching_nonexistent_key(self):
        self.redis.set('foo', 'bar')
        self.redis.rpush('greet', 'hello')
        p = self.redis.pipeline()
        try:
            # Also watch a nonexistent key.
            p.watch('foo', 'bam')
            nextf = fakeredis.to_bytes(p.get('foo')) + b'baz'
            # Simulate change happening on another thread.
            self.redis.rpush('greet', 'world')
            p.multi()
            p.set('foo', nextf)
            p.execute()

            # Check the commands were executed.
            self.assertEqual(self.redis.get('foo'), b'barbaz')
        finally:
            p.reset()

def test_pipeline_raises_when_watched_key_changed(self):
        self.redis.set('foo', 'bar')
        self.redis.rpush('greet', 'hello')
        p = self.redis.pipeline()
        self.addCleanup(p.reset)

        p.watch('greet', 'foo')
        nextf = fakeredis.to_bytes(p.get('foo')) + b'baz'
        # Simulate change happening on another thread.
        self.redis.rpush('greet', 'world')
        # Begin pipelining.
        p.multi()
        p.set('foo', nextf)

        with self.assertRaises(redis.WatchError):
            p.execute()