```doc
# Shift Left

Values which wish to implement the `<<` infix operator must implement this protocol.
```
protocol ShiftLeft, as:
  ```doc
  Shift `lhs` left by `rhs` bits, returning an option.

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