YAML: Keys like "yes" or "no" evaluate to true and false

If you parse this Yaml ...

Copyyes: 'Totally'
no: 'Nope'

... you get this Ruby hash:

Copy{ true: 'Totally',
  false: 'Nope' }

In order to use the strings 'yes' and 'no' as keys, you need to wrap them with quotes:

Copy'yes': 'Totally'
'no': 'Nope'

There's actually a long list of reserved words Show archive.org snapshot with this behavior:

Copyy|Y|yes|Yes|YES|n|N|no|No|NO
|true|True|TRUE|false|False|FALSE
|on|On|ON|off|Off|OFF

I'm sorry.