<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _get_checked_errors(cls, options):
 """Extract the codes needed to be checked from `options`."""

        checked_codes = cls._get_exclusive_error_codes(options)
        if checked_codes is None:
            checked_codes = cls.DEFAULT_CONVENTION

        cls._set_add_options(checked_codes, options)

        return checked_codes