how to escape the pipe character ("|") in yaml files as key?

Is there an explicit way to escape the | character in yaml files?
I don’t want to use the pipe literal, but the character itself.

I tried the following yaml:
"A||B": "ASCENDING"

Tried also:
"A\|\|B": "ASCENDING"

but when reading the yaml I see:
"AB": "ASCENDING"

>Solution :

You should wrap it with the square brackets "[A||B]"