Microsoft .NET Framework SDK directory.

def NetFxSdkDir(self):
        """
        Microsoft .NET Framework SDK directory.
        """
        for ver in self.NetFxSdkVersion:
            loc = os.path.join(self.ri.netfx_sdk, ver)
            sdkdir = self.ri.lookup(loc, 'kitsinstallationfolder')
            if sdkdir:
                break
        return sdkdir or ''