def default(cls, is_cross: bool, build: _T, host: _T) -> PerMachine[_T]:
        """Easy way to get a defaulted value

        This allows simplifying the case where you can control whether host and
        build are separate or not with a boolean. If the is_cross value is set
        to true then the optional host value will be used, otherwise the host
        will be set to the build value.
        """
        m = cls(build)
        if is_cross:
            m.host = host
        return m.default_missing()
Easy way to get a defaulted value

        This allows simplifying the case where you can control whether host and
        build are separate or not with a boolean. If the is_cross value is set
        to true then the optional host value will be used, otherwise the host
        will be set to the build value.
        
mesonbuild/utils/universal.py