no method named map_err found for enum Option in the current scope

[sgtnasty]

I cant seem to find any solutions to this online, but it appears map_err does not exist for Option. Do I need to create a method for it? I am confused at this point how to approach.

Here is the code:

    fn explains_why_generating_nametag_text_fails() {
        assert_eq!(
            generate_nametag_text(String::new())
                .as_ref()
                .map_err(|e| e.as_str()),
            Err("Empty names aren't allowed"),
        );
    }

Errors show as:

error[E0599]: no method named `map_err` found for enum `Option` in the current scope
    --> exercises/13_error_handling/errors1.rs:37:18
     |
35   | /             generate_nametag_text(String::new())
36   | |                 .as_ref()
37   | |                 .map_err(|e| e.as_str()),
     | |_________________-^^^^^^^
     |
help: there is a method `map_or` with a similar name, but with different arguments
    --> /home/ronaldo/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/option.rs:1159:5
     |
1159 | /     pub fn map_or<U, F>(self, default: U, f: F) -> U
1160 | |     where
1161 | |         F: FnOnce(T) -> U,
     | |__________________________^

[sgtnasty]

I just needed to re-read the header of the exercise and I figured out I needed to change the Option to a Result.