def post(self, value, addend, unit):
        """A date adder endpoint."""
        value = value or dt.datetime.utcnow()
        if unit == "minutes":
            delta = dt.timedelta(minutes=addend)
        else:
            delta = dt.timedelta(days=addend)
        result = value + delta
        return {"result": result.isoformat()}
A date adder endpoint.