Process line.

        Overwrite BaseFilter.accept() and return True if the provided
        logevent should be accepted (causing output), or False if not.

def accept(self, logevent):
        """
        Process line.

        Overwrite BaseFilter.accept() and return True if the provided
        logevent should be accepted (causing output), or False if not.
        """
        if self.active and logevent.duration is not None:
            return logevent.duration <= self.fastms
        return False