def top_or_none(cls):
        """Get the TOS or return None if no config is set.
        """
        self = cls()
        if self:
            flags = self.top()
        else:
            # Note: should this be the default flag for the target instead?
            flags = None
        return flags
Get the TOS or return None if no config is set.
        
numba/core/targetconfig.py