tls_client imports `typing_extensions` at load and it is not installed. Run `python -m pip install typing_extensions` (or reinstall tls-client normally so pip resolves it). The import works right after.

## The error

```text
ModuleNotFoundError: No module named 'typing_extensions'
```

## Fix it

1. **Install typing_extensions**

```
python -m pip install typing_extensions
```
Expected: `Successfully installed typing_extensions-...`.

2. **Confirm the chain**

```
python -c "import tls_client; print('ok')"
```
Expected: prints `ok`.

3. **If it recurs, reinstall tls-client with dependencies**

```
python -m pip install --force-reinstall tls-client
```
Expected: pip restores the declared dependency set.

## When this applies

- `import tls_client` fails naming `typing_extensions`
- the traceback shows tls_client's own modules importing it
- a `--no-deps` install or a minimal image

## When it does NOT apply

- `No module named 'tls_client'` is the parent package missing

## Compatibility

All tls-client 1.x/2.x declare typing_extensions. typing_extensions itself supports Python 3.8+.

## Why it happens

typing_extensions backports new typing features to older Pythons, and tls_client uses them at import time. It is a declared dependency, so its absence means the install was done with `--no-deps`, a resolver glitch, or a hand-pruned requirements file.

## Edge cases

- On Python 3.11+, much of typing_extensions is redundant, but tls_client still imports the package itself, so it must be present regardless.