''

def parse_limit_offset(self, qdict):

    def _parse_pos_int(i):
        try:
            new_val = int(i)
            if (new_val >= 0):
                return new_val
        except (TypeError, ValueError):
            pass
        return None
    limit = _parse_pos_int(qdict.get('limit', None))
    offset = _parse_pos_int(qdict.get('offset', None))
    return (limit, offset)
