Works in 3.6+

```
random.choices([1,2], weights=[0.001, 0.8], k=1)[0]
```

Here is proof that makes 100k choices from `[1,2]`

array and then counts numbers:

```
arr = [ch[0] for ch in [random.choices([1,2], weights=[0.001, 0.8], k=1) for _ in range(100000)]]
>>> arr.count(1), arr.count(2)
(114, 99886)
```