def _assert_mutually_exclusive(
        self, params_assigned_from_default: Set[str], group: List[str]
    ) -> None:
        """
        Ensure no elements from group are simultaneously provided by a user, as inferred from params_assigned_from_default.
        Raises click.UsageError if any two elements from group are simultaneously provided by a user.
        """
        set_flag = None
        for flag in group:
            flag_set_by_user = (
                hasattr(self, flag) and flag.lower() not in params_assigned_from_default
            )
            if flag_set_by_user and set_flag:
                raise DbtUsageException(
                    f"{flag.lower()}: not allowed with argument {set_flag.lower()}"
                )
            elif flag_set_by_user:
                set_flag = flag

        Ensure no elements from group are simultaneously provided by a user, as inferred from params_assigned_from_default.
        Raises click.UsageError if any two elements from group are simultaneously provided by a user.
        
core/dbt/cli/flags.py