简单解决python安装中的Unable to find vcvarsall.bat问题

def _find_vcvarsall(plat_spec):
    try:
        key = winreg.OpenKeyEx(
            winreg.HKEY_LOCAL_MACHINE,
            r"Software\Microsoft\VisualStudio\SxS\VC7",
            access=winreg.KEY_READ | winreg.KEY_WOW64_32KEY
        )
    except OSError:
        log.debug("Visual C++ is not registered")
        return None, None

    with key:
        best_version = 0
        best_dir = None
        for i in count():
            try:
                v, vc_dir, vt = winreg.EnumValue(key, i)
            except OSError:
                break
            if v and vt == winreg.REG_SZ and os.path.isdir(vc_dir):
                try:
                    version = int(float(v))
                except (ValueError, TypeError):
                    continue
                if version >= 14 and version > best_version:
                    best_version, best_dir = version, vc_dir
        if not best_version:
            log.debug("No suitable Visual C++ version found")
            return None, None

        vcvarsall = os.path.join(best_dir, "vcvarsall.bat")
        if not os.path.isfile(vcvarsall):
            log.debug("%s cannot be found", vcvarsall)
            return None, None

        vcruntime = None
        vcruntime_spec = _VCVARS_PLAT_TO_VCRUNTIME_REDIST.get(plat_spec)
        if vcruntime_spec:
            vcruntime = os.path.join(best_dir,
                vcruntime_spec.format(best_version))
            if not os.path.isfile(vcruntime):
                log.debug("%s cannot be found", vcruntime)
                vcruntime = None

        return vcvarsall, vcruntime

def _find_vcvarsall(plat_spec):
        best_dir = r'E:\tools\vs2017\VC\Auxiliary\Build'
        best_version = 17
        vcruntime = None
        vcruntime_spec = _VCVARS_PLAT_TO_VCRUNTIME_REDIST.get(plat_spec)
        if vcruntime_spec:
            vcruntime = os.path.join(best_dir,
                vcruntime_spec.format(best_version))
            if not os.path.isfile(vcruntime):
                log.debug("%s cannot be found", vcruntime)
                vcruntime = None
        print(vcruntime)
        return r'E:\tools\vs2017\VC\Auxiliary\Build\vcvarsall.bat', vcruntime