human
Solve the following python programming problem given the following code:
@optional_args
def network(t, url='http://www.google.com', raise_on_error=_RAISE_NETWORK_ERROR_DEFAULT, check_before_test=False, error_classes=_network_error_classes, skip_errnos=_network_errno_vals, _skip_on_messages=_network_error_messages):
assistant
#Here is the Python program you requested.

    """Label a test as requiring network connection and, if an error is
    encountered, only raise if it does not find a network connection.
    In comparison to ``network``, this assumes an added contract to your test:
    you must assert that, under normal conditions, your test will ONLY fail if
    it does not have network connectivity.
    You can call this in 3 ways: as a standard decorator, with keyword
    arguments, or with a positional argument that is the url to check.
    Parameters
    t : callable
    The test requiring network connectivity.
    url : path
    The url to test via ``pandas.io.common.urlopen`` to check
    for connectivity. Defaults to \http://www.google.com\.
    raise_on_error : bool
    If True, never catches errors.
    check_before_test : bool
    If True, checks connectivity before running the test case.
    error_classes : tuple or Exception
    error classes to ignore. If not in ``error_classes``, raises the error.
    defaults to IOError. Be careful about changing the error classes here.
    skip_errnos : iterable of int
    Any exception that has .errno or .reason.erno set to one
    of these values will be skipped with an appropriate
    message.
    _skip_on_messages: iterable of string
    any exception e for which one of the strings is
    a substring of str(e) will be skipped with an appropriate
    message. Intended to supress errors where an errno isn\t available.
    Notes
    * ``raise_on_error`` supercedes ``check_before_test``
    Returns
    t : callable
    The decorated test ``t``, with checks for connectivity errors.
    Example
    Tests decorated with @network will fail if it\s possible to make a network
    connection to another URL (defaults to google.com)::
    >>> from pandas.util.testing import network
    >>> from pandas.io.common import urlopen
    >>> @network
    ... def test_network():
    ...     with urlopen("rabbit://bonanza.com"):
    ...         pass
    Traceback
    URLError: <urlopen error unknown url type: rabit>
    You can specify..."""
    from pytest import skip
    t.network = True
    @wraps(t)
    def wrapper(*args, **kwargs):
        if (check_before_test and (not raise_on_error)):
            if (not can_connect(url, error_classes)):
                skip()
        try:
            return t(*args, **kwargs)
        except Exception as e:
            errno = getattr(e, 'errno', None)
            if ((not errno) and hasattr(errno, 'reason')):
                errno = getattr(e.reason, 'errno', None)
            if (errno in skip_errnos):
                skip(('Skipping    test    due    to    known    errno    and    error    %s' % e))
            try:
                e_str = traceback.format_exc(e)
            except:
                e_str = str(e)
            if any([(m.lower() in e_str.lower()) for m in _skip_on_messages]):
                skip(('Skipping    test    because    exception    message    is    known    and    error    %s' % e))
            if (not isinstance(e, error_classes)):
                raise
            if (raise_on_error or can_connect(url, error_classes)):
                raise
            else:
                skip(('Skipping    test    due    to    lack    of    connectivity    and    error    %s' % e))
    return wrapper