Internal method that looks up a key in the local cache.
    :param key: Get the value based on the key from the cache.
    :type key: string
    :returns: void

def _lookup(key):
    """
    Internal method that looks up a key in the local cache.
    :param key: Get the value based on the key from the cache.
    :type key: string
    :returns: void
    """
    if key not in _CACHE:
        return None
    if _CACHE_COUNTER[key] >= len(_CACHE[key][1:]):
        if _CACHE[key][0] == "empty":
            return ""
        elif _CACHE[key][0] == "repeat" and _CACHE[key][1:]:
            return _CACHE[key][-1]
        elif _CACHE[key][0] == "repeat":
            return ""
        else:
            _CACHE_COUNTER[key] = 1
    else:
        _CACHE_COUNTER[key] += 1
    if _CACHE[key]:
        return _CACHE[key][_CACHE_COUNTER[key]]
    else:
        return ""