urlopen with multiple retries

A good example from test_urllib2net

def _retry_thrice(func, exc, *args, **kwargs):

    for i in range(3):

        try:

            return func(*args, **kwargs)

        except exc, last_exc:

            continue

        except:

            raise

    raise last_exc

def _wrap_with_retry_thrice(func, exc):

    def wrapped(*args, **kwargs):

        return _retry_thrice(func, exc, *args, **kwargs)

    return wrapped

# Connecting to remote hosts is flaky.  Make it more robust by retrying

# the connection several times.

_urlopen_with_retry = _wrap_with_retry_thrice(urllib2.urlopen, urllib2.URLError)