forgive
forgive can take an optional default argument
Forgive turns error values into nils. It can be given an optional second argument,
which it will return instead of nil.
This is useful if you have a transformation where you don't care if it fails.
Examples:
forgive(error('hello'), 'no errors here')
-- Result: "no errors here"
forgive('not an error', 'hello')
-- Result: "not an error"
forgive(error('hello'))
-- Result: null
forgive('not an error')
-- Result: "not an error"
a, a -> a
a -> a