YAMLish parse bug when no value present

[paulprocacci]

Edit: I just saw you're TODO. Sorry about that. I'm going to leave this here because it is indeed a bug.

some:
user:
    - username

Given the above example, YAMLish parses the above as:

some => {user => [username]}

Python's YAML module parses it as:

'some': None, 'user': ['username']

Given the indenting here, I suspect the YAMLish parser has gotten this wrong.
In fact, the specification says it's wrong:

https://yaml.org/spec/1.2.2/#22-structures

Section: 2.21 Example

[FCO]

And:

bla:
ble:

Is not parsed: