def _create_query(self) -> orm.Query:
    '\n        Must be implemented by subclasses to return an instance of a SQLAlchemy\n        query which only returns MRNs.\n\n        This query should yield all medical record numbers in the\n        ``base_table`` of the condition. It uses the ``.clause`` to select\n        the relevant patients.\n\n        This query is also used by other function which change the selected\n        columns to get data about the patients.\n        '
    raise NotImplementedError
Must be implemented by subclasses to return an instance of a SQLAlchemy
query which only returns MRNs.

This query should yield all medical record numbers in the
``base_table`` of the condition. It uses the ``.clause`` to select
the relevant patients.

This query is also used by other function which change the selected
columns to get data about the patients.
def _create_query(self) -> orm.Query:
    '\n        Must be implemented by subclasses to return an instance of a SQLAlchemy\n        query which only returns MRNs.\n\n        This query should yield all medical record numbers in the\n        ``base_table`` of the condition. It uses the ``.clause`` to select\n        the relevant patients.\n\n        This query is also used by other function which change the selected\n        columns to get data about the patients.\n        '
    raise NotImplementedError