Function filter

filter<V>(it: Iterable<V>, f: (v: V) => boolean): Generator<V, void, unknown>
```
filter([1, 2, 3, 4], e => e % 2 == 0);
returns [2, 4]
```
Type Parameters
- V
Parameters
- it: Iterable<V>
- f: (v: V) => boolean
Returns Generator<V, void, unknown>