sqlalchemy.orm.exc.ObjectDeletedError

A refresh operation failed to retrieve the database row corresponding to an object's known primary key identity. A refresh operation proceeds when an expired attribute is accessed on an object, or when :meth:`_query.Query.get` is used to retrieve an object which is, upon retrieval, detected as expired. A SELECT is emitted for the target row based on primary key; if no row is returned, this exception is raised. The true meaning of this exception is simply that no row exists for the primary key identifier associated with a persistent object. The row may have been deleted, or in some cases the primary key updated to a new value, outside of the ORM's management of the target object.