sqlalchemy.orm.strategies.LoadLazyAttribute

semi-serializable loader object used by LazyLoader

Historically, this object would be carried along with instances that needed to run lazyloaders, so it had to be serializable to support cached instances.

this is no longer a general requirement, and the case where this object is used is exactly the case where we can't really serialize easily, which is when extra criteria in the loader option is present.

We can't reliably serialize that as it refers to mapped entities and AliasedClass objects that are local to the current process, which would need to be matched up on deserialize e.g. the sqlalchemy.ext.serializer approach.