Pipelines api query parameter order_by does not work

Hi,

While searching though pipelines API, I wanted to load pipelines from oldest first in order to purge them. To do so, I requested the pipelines API requesting order_by with the value updated_at or created_at. Neither of these values are accepted and ends with the error message:

{"error":"order_by does not have a valid value"}

I don't know if I well did everything

Thank you.