Internal method to add a new key-value to the local cache.
    :param str key: The new url to add to the cache
    :param str value: The HTTP response for this key.
    :returns: void

def _add_to_cache(key, value):
    """
    Internal method to add a new key-value to the local cache.
    :param str key: The new url to add to the cache
    :param str value: The HTTP response for this key.
    :returns: void
    """
    if key in _CACHE:
        _CACHE[key].append(value)
    else:
        _CACHE[key] = [_PATTERN, value]
        _CACHE_COUNTER[key] = 0