microsoft/qlib · error · NotImplementedError

Subclass of CalendarStorage must implement `data` method

Error message

Subclass of CalendarStorage must implement `data` method

What it means

Error "Subclass of CalendarStorage must implement `data` method" thrown in microsoft/qlib.

Source

Thrown at qlib/data/storage/storage.py:35

InstKT = Text

logger = get_module_logger("storage")

"""
If the user is only using it in `qlib`, you can customize Storage to implement only the following methods:

class UserCalendarStorage(CalendarStorage):

    @property
    def data(self) -> Iterable[CalVT]:
        '''get all data

        Raises
        ------
        ValueError
            If the data(storage) does not exist, raise ValueError
        '''
        raise NotImplementedError("Subclass of CalendarStorage must implement `data` method")


class UserInstrumentStorage(InstrumentStorage):

    @property
    def data(self) -> Dict[InstKT, InstVT]:
        '''get all data

        Raises
        ------
        ValueError
            If the data(storage) does not exist, raise ValueError
        '''
        raise NotImplementedError("Subclass of InstrumentStorage must implement `data` method")


class UserFeatureStorage(FeatureStorage):

View on GitHub (pinned to 79633dd950)

Solutions

1. Implement the `data` method in your CalendarStorage subclass.
2. Use the built-in FileCalendarStorage which implements `data`.

When it happens

Trigger: This error is raised at qlib/data/storage/storage.py:35 when the guard condition fails: "Subclass of CalendarStorage must implement `data` method". It triggers when the code path receives input or a state that violates the precondition checked at this point — e.g. an unimplemented abstract method being called, an unsupported argument type/value, or an invalid configuration. To avoid it, satisfy the documented precondition before this call: implement the required method in your subclass, or pass a supported value of the expected type as described by the message.

Common situations: See trigger scenarios.

AI-assisted analysis of microsoft/qlib@79633dd950 (2026-08-15). Data as JSON: /api/errors/d43917d7724960fc. Report an issue: GitHub.