Support for timestamp in dateformat

[Glandos]

I am integrating https://github.com/alisaifee/flask-limiter and a RequestLimit has a timestamp instead of a datetime object.
Currently, it's not possible to format timestamp directly in the template, so I have to either add a custom filter or parse the timestamp before rendering.

Is it possible to add an optional parameter timestamp defaulted to False to parse dates?