I have the following code that basically converts strings to Enums where applicable:

        func value(for key: String) -> String? {
            return values(for: key).first
        }

        func anyValue<T: LosslessStringConvertible>(for key: String) -> T? {
            guard let value = value(for: key) else { return nil }

            return T(value)
        }

        func enumValue<EnumType, ValueType>(for key: String) -> EnumType? where EnumType: RawRepresentable<ValueType>, ValueType: LosslessStringConvertible {
            guard let value: ValueType = anyValue(for: key) else { return nil }

            return EnumType(rawValue: value)
        }


        func enumValue<EnumType, ValueType>(for key: String) -> EnumType? where EnumType: RawRepresentable<ValueType?>, ValueType: LosslessStringConvertible {
            guard let value: ValueType = anyValue(for: key) else { return nil }

            return EnumType(rawValue: value)
        }

Is it possible to combine the two versions of enumValue into one generic without any new protocols or extensions? I want to be able to use it with a RawRepresentable<Int> as well as a RawRepresentable<Int?>.