use Any
use Option

```doc
# Exponentiation

Values which wish to implement the `**` infix operator must implement this protocol.
```
protocol Exponentiation, as: do
  ```doc
  Raise `self` to the power of `other`, returning an option.

  It is left up to the implementer to define when it should return `Some` or `None`.
  ```
  def raise(self: Self, other: Any): Option
end