def is_valid_url(s):
    try:
        validate_url(s)
        return True
    except ValidationError:
        return False
Referrer URL of request as a string, or None.
dataset/ETHPy150Open lsaffre/lino/lino/core/utils.py/is_valid_url--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/api/logservice/logservice.py/RequestLog.referrer