class Dry::Types::Maybe

def call_safe(input = Undefined, &block)
  case input
  when Dry::Monads::Maybe
    input
  when Undefined
    None()
  else
    Maybe(type.call_safe(input, &block))
  end
end

def call_unsafe(input = Undefined)
  case input
  when Dry::Monads::Maybe
    input
  when Undefined
    None()
  else
    Maybe(type.call_unsafe(input))
  end
end

def default(value)
  if value.nil?
    raise ArgumentError, 'nil cannot be used as a default of a maybe type'
  else
    super
  end
end

def default?
  true
end

def try(input = Undefined)
  res = if input.equal?(Undefined)
          None()
        else
          Maybe(type[input])
        end
  Result::Success.new(res)
end