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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 find_info(name=None):
 """Find the needed city server information."""

    if not name:
        return list(servers.keys()) 
    name = name.lower()
    if name in servers:
        info = servers[name]
    else:
        raise CityNotFound("Could not find the specified city: %s" % name)
    return info