microsoft/qlib · error · NotImplementedError

Please implement the `load_obj` method

Error message

Please implement the `load_obj` method

What it means

load_obj(name) is the read primitive of the abstract ObjManager interface; the base stub raises NotImplementedError. It fires when objects are loaded through the abstract base class or through a subclass that never implemented loading — a common failure for custom managers written write-only.

Source

Thrown at qlib/utils/objm.py:50

        obj_name_l : list of <obj, name>
        """
        raise NotImplementedError(f"Please implement the `save_objs` method")

    def load_obj(self, name: str) -> object:
        """
        load object by name

        Parameters
        ----------
        name : str
            the name of the object

        Returns
        -------
        object:
            loaded object
        """
        raise NotImplementedError(f"Please implement the `load_obj` method")

    def exists(self, name: str) -> bool:
        """
        if the object named `name` exists

        Parameters
        ----------
        name : str
            name of the objecT

        Returns
        -------
        bool:
            If the object exists
        """
        raise NotImplementedError(f"Please implement the `exists` method")

    def list(self) -> list:

View on GitHub (pinned to 79633dd950)

Solutions

1. Use FileManager for local-disk persistence; its load_obj unpickles from self.path/name.
2. Implement load_obj(self, name) -> object in your subclass, returning the deserialized object.
3. Verify with hasattr/inspect before dispatching: ensure the manager instance overrides load_obj before calling it.

Example fix

// before
obj = ObjManager().load_obj('model_v1')  # NotImplementedError

// after
obj = FileManager(path='./objs').load_obj('model_v1')

from qlib.utils.objm import ObjManager
assert type(mgr).load_obj is not ObjManager.load_obj, 'manager cannot load objects'

def can_load(mgr) -> bool:
    return type(mgr).load_obj is not ObjManager.load_obj

try:
    obj = mgr.load_obj(name)
except NotImplementedError:
    obj = FileManager(path='./objs').load_obj(name)

When it happens

Trigger: ObjManager().load_obj('name'), or a custom manager implementing save_obj/save_objs but not load_obj; qlib internals calling obj_manager.load_obj(...) on an incompletely-configured manager.

Common situations: Restoring trained models/artifacts in a later session via a custom manager class; qlib workflow recorder code paths that fetch cached datasets/processors; upgrading qlib where the manager interface gained stricter abstractness.

Related errors

• Please implement `save_obj`
• Please implement the `save_objs` method
• Please implement the `exists` method
• Please implement the `list` method
• Please implement the `remove` method

AI-assisted analysis of microsoft/qlib@79633dd950 (2026-08-15). Data as JSON: /api/errors/03cc21cdad3cbb3d. Report an issue: GitHub.