def find_reg_vs_vers(self):
        """
        Find Microsoft Visual Studio versions available in registry.

        Return
        ------
        list of float
            Versions
        """
        ms = self.ri.microsoft
        vckeys = (self.ri.vc, self.ri.vc_for_python, self.ri.vs)
        vs_vers = []
        for hkey, key in itertools.product(self.ri.HKEYS, vckeys):
            try:
                bkey = winreg.OpenKey(hkey, ms(key), 0, winreg.KEY_READ)
            except (OSError, IOError):
                continue
            with bkey:
                subkeys, values, _ = winreg.QueryInfoKey(bkey)
                for i in range(values):
                    with contextlib.suppress(ValueError):
                        ver = float(winreg.EnumValue(bkey, i)[0])
                        if ver not in vs_vers:
                            vs_vers.append(ver)
                for i in range(subkeys):
                    with contextlib.suppress(ValueError):
                        ver = float(winreg.EnumKey(bkey, i))
                        if ver not in vs_vers:
                            vs_vers.append(ver)
        return sorted(vs_vers)

        Find Microsoft Visual Studio versions available in registry.

        Return
        ------
        list of float
            Versions
        
product/gradle-plugin/src/main/python/setuptools/msvc.py