I would like a function to include a type hint for NumPy `ndarray`'s alongside with its `dtype`.

With lists, for example, one could do the following...

```
def foo(bar: List[int]):
   ...

```

...in order to give a type hint that `bar` has to be `list` consisting of `int`'s.

Unfortunately, this syntax throws exceptions for NumPy `ndarray`:

```
def foo(bar: np.ndarray[np.bool]):
   ...

> np.ndarray[np.bool]) (...) TypeError: 'type' object is not subscriptable

```

Is it possible to give `dtype`-specific type hints for `np.ndarray`?