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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def is_source_ip_already_locked(ip_address):
 """Is this IP already locked?"""

    if ip_address is None:
        return False
    if config.DISABLE_IP_LOCKOUT:
        return False
    return REDIS_SERVER.get(get_ip_blocked_cache_key(ip_address))