`len(object_id)` should raise an exception.

[robertnishihara]

x_id = ray.put(1)
print(len(x_id))  # '20'

Instead of returning 20, this should raise an exception. If someone is calling len on a ray.ObjectID it is almost certainly a bug (in particular, they think that a remote function is returning a list of object IDs, but in fact it is returning 1 object ID.

[hpandeycodeit]

@robertnishihara I will do it.