def has_indexes_changed(old_model_sig, new_model_sig):
    """Return whether indexes have changed between signatures.

    Args:
        old_model_sig (dict):
            Old signature for the model.

        new_model_sig (dict):
            New signature for the model.

    Returns:
        bool:
        ```True``` if there are any differences in indexes.
    """
    return (old_model_sig['meta'].get('indexes', []) !=
            new_model_sig['meta'].get('indexes', []))