@classmethod<EOL><INDENT>def _get_exclusive_error_codes(cls, options):<DEDENT>
codes = set(ErrorRegistry.get_error_codes())<EOL>checked_codes = None<EOL>if options.ignore is not None:<EOL><INDENT>ignored = cls._expand_error_codes(options.ignore)<EOL>checked_codes = codes - ignored<EOL><DEDENT>elif options.select is not None:<EOL><INDENT>checked_codes = cls._expand_error_codes(options.select)<EOL><DEDENT>elif options.convention is not None:<EOL><INDENT>checked_codes = getattr(conventions, options.convention)<EOL><DEDENT>return copy.deepcopy(checked_codes)<EOL>
Extract the error codes from the selected exclusive option.