Result

Represents a state of success or failure, declaring a type for each. It is the monadic way to error handling. A Result instance will either be an Ok object wrapping a value of the success type T, or an Err object wrapping a value of the failure type E.

• Mapping a function over an Err will return the Err unchanged without calling the function.
• Binding an operation with an Err will return the Err unchanged without attempting the operation.

m: Result[int, str] = Ok(5)
increment: Callable[[int],int] = lambda x : x +1
Ok(6) == m.map(increment)
e: Result[int, str] = Err("oops")
Err("oops") == e.map(increment) # still an error