Pop 
by Anthony Fu @antfu
> TypeScript 4.0 is recommended in this challenge
Implement a generic `Pop` that takes an Array `T` and returns an Array without it's last element.
For example
```ts
type arr1 = ['a', 'b', 'c', 'd']
type arr2 = [3, 2, 1]
type re1 = Pop // expected to be ['a', 'b', 'c']
type re2 = Pop // expected to be [3, 2]
```
**Extra**: Similarly, can you implement `Shift`, `Push` and `Unshift` as well?
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