Set multiple values in devops library variable

[TejRebba]

Hi 

I need to pass multiple values in Library variable in DevOps.

Currently my YAML looks like below.

Contents: |
RepoFolder1\*.txt
RepoFolder2\*.csv
RepoFolder3\*.py

I want to create variable and pass above values to library variable in DevOps like below.

Contents: $(Source_Files)

Somehow Library variable is plain text, and it is not allowing multiline. How to achieve this.

Thanks,

Siva.